Mypaint closes by itself after a few minutes on debian buster

[Witch-Kaira]

I'm using debian buster since february of the last year and since then I've been having this problem with Mypaint. I'm using the version 1.2.0+gitexport.f62444e that comes in the repository, and after a few minutes drawing it closes by itself, the moment that it happens is random, but it usually happens after 2 minutes or less and sometimes it takes several minutes to happen, I noticed that it happens more frequently after I save my progress, I press ctrl+s and after 1 or 2 minutes the software closes, sometimes it closes after a few seconds too, all the rest works fine but it keeps closing by itself every time. I also noticed a few weeks ago that it's not saving the progress automatically anymore either, every time the software closed and I opened it again it always used to show a window with recovery files of the drawings I did, but now it doesn't appear anymore, instead it appears a window saying that a programming error was detected, I don't know what to do. I've been using Mypaint since 2012 and never had any problems before, I also tried the version 2.0 but it's even worse, when I click in some of those tools on the top of the screen Mypaint closes too.
I can't take that red background anymore, I can use another color but everytime I open Mypaint or load a file there it comes red everytime.
I'll leave the whole terminal process and another error window showing the lines that appear on that programing error, the image is in portuguese cause I'm brazilian, but all the error messages are in english.
I also noticed that when I'm using only the mouse with the wacom disconnected Mypaint doesn't close, but the same programming error and also the errors on terminal continues to appear, I'm using a Wacom Bamboo Connect Pen CTL-470, the same I've been using since 2012.

MyPaint version: 1.2.0+gitexport.f62444e
Operating system: Debian 10.10
Desktop environment: KDE

Steps to reproduce:

1. Start MyPaint
2. Draw for a few minutes and it closes, no recovery option available
3. Draw for a few minutes or seconds after pressing ctrl+s and it closes, no recovery option available

kaira@darkness:~$ mypaint
INFO: mypaint: Installation layout: conventional POSIX-like structure with prefix u'/usr'
INFO: lib.i18n: POSIX: LANG='pt_BR.UTF-8'
INFO: lib.i18n: POSIX: LANGUAGE=''

(mypaint:17434): Gtk-WARNING **: 23:59:46.971: Theme parsing error: gtk.css:127:35: The style property GtkButton:child-displacement-x is deprecated and shouldn't be used anymore. It will be removed in a future version

(mypaint:17434): Gtk-WARNING **: 23:59:46.971: Theme parsing error: gtk.css:128:35: The style property GtkButton:child-displacement-y is deprecated and shouldn't be used anymore. It will be removed in a future version

(mypaint:17434): Gtk-WARNING **: 23:59:46.971: Theme parsing error: gtk.css:129:34: The style property GtkCheckButton:indicator-size is deprecated and shouldn't be used anymore. It will be removed in a future version

(mypaint:17434): Gtk-WARNING **: 23:59:46.971: Theme parsing error: gtk.css:130:36: The style property GtkCheckMenuItem:indicator-size is deprecated and shouldn't be used anymore. It will be removed in a future version

(mypaint:17434): Gtk-WARNING **: 23:59:46.971: Theme parsing error: gtk.css:132:46: The style property GtkScrolledWindow:scrollbars-within-bevel is deprecated and shouldn't be used anymore. It will be removed in a future version

(mypaint:17434): Gtk-WARNING **: 23:59:46.972: Theme parsing error: gtk.css:135:30: The style property GtkExpander:expander-size is deprecated and shouldn't be used anymore. It will be removed in a future version

(mypaint:17434): Gtk-WARNING **: 23:59:46.972: Theme parsing error: gtk.css:142:29: The style property GtkStatusbar:shadow-type is deprecated and shouldn't be used anymore. It will be removed in a future version
INFO: gui.device: New device 'Wacom Bamboo Connect Pad pad' (GDK_SOURCE_TABLET_PAD, axes:6, class=X11DeviceXI2, vendor='056a', product='00dd')                      
INFO: gui.device: New device 'Wacom Bamboo Connect Pen eraser' (GDK_SOURCE_ERASER, axes:6, class=X11DeviceXI2, vendor='056a', product='00dd')                       
INFO: gui.device: New device 'Wacom Bamboo Connect Pen stylus' (GDK_SOURCE_PEN, axes:6, class=X11DeviceXI2, vendor='056a', product='00dd')                          
INFO: gui.device: New device 'ImPS/2 Generic Wheel Mouse' (GDK_SOURCE_MOUSE, axes:4, class=X11DeviceXI2, vendor='0002', product='0005')                             
INFO: gui.device: New device 'Virtual core XTEST pointer' (GDK_SOURCE_MOUSE, axes:2, class=X11DeviceXI2, vendor=None, product=None)                                 
INFO: gui.document: Initialized background from u'/home/kaira/.local/share/mypaint/backgrounds/default.png'
WARNING: gui.keyboard: Ignoring keybinding for '<Actions>/BrushModifierActions/BlendModeMenu'

(mypaint:17434): Gtk-WARNING **: 23:59:47.933: Theme parsing error: <data>:5:50: The style property GtkMenuBar:internal-padding is deprecated and shouldn't be used anymore. It will be removed in a future version

(mypaint:17434): Gtk-WARNING **: 23:59:48.205: Theme parsing error: gtk.css:68:35: The style property GtkButton:child-displacement-x is deprecated and shouldn't be used anymore. It will be removed in a future version

(mypaint:17434): Gtk-WARNING **: 23:59:48.205: Theme parsing error: gtk.css:69:35: The style property GtkButton:child-displacement-y is deprecated and shouldn't be used anymore. It will be removed in a future version

(mypaint:17434): Gtk-WARNING **: 23:59:48.205: Theme parsing error: gtk.css:70:34: The style property GtkCheckButton:indicator-size is deprecated and shouldn't be used anymore. It will be removed in a future version

(mypaint:17434): Gtk-WARNING **: 23:59:48.206: Theme parsing error: gtk.css:71:36: The style property GtkCheckMenuItem:indicator-size is deprecated and shouldn't be used anymore. It will be removed in a future version

(mypaint:17434): Gtk-WARNING **: 23:59:48.206: Theme parsing error: gtk.css:73:46: The style property GtkScrolledWindow:scrollbars-within-bevel is deprecated and shouldn't be used anymore. It will be removed in a future version

(mypaint:17434): Gtk-WARNING **: 23:59:48.206: Theme parsing error: gtk.css:76:30: The style property GtkExpander:expander-size is deprecated and shouldn't be used anymore. It will be removed in a future version

(mypaint:17434): Gtk-WARNING **: 23:59:48.206: Theme parsing error: gtk.css:83:29: The style property GtkStatusbar:shadow-type is deprecated and shouldn't be used anymore. It will be removed in a future version
INFO: lib.document: Using u'load_ora' to load u'/home/kaira/.local/share/mypaint/scratchpads/autosave.ora' (kwargs={'feedback_cb': <function gtk_main_tick at 0x7fa3b18b06e0>})                                                                       
INFO: lib.document: load_ora: u'/home/kaira/.local/share/mypaint/scratchpads/autosave.ora'
INFO: lib.document: 0.077s load_ora total
INFO: gui.filehandling: Loaded scratchpad from u'/home/kaira/.local/share/mypaint/scratchpads/autosave.ora'
WARNING: gui.accelmap: Not listing '<Actions>/DocumentActions/RotateLeft' (no tooltip, fix before release!)                                                         
WARNING: gui.accelmap: Not listing '<Actions>/DocumentActions/RotateRight' (no tooltip, fix before release!)                                                        
Traceback (most recent call last):
  File "/usr/share/mypaint/gui/application.py", line 412, in _at_application_start
    autosave_recovery.run()
  File "/usr/share/mypaint/gui/autorecover.py", line 114, in run
    desc = autosave.get_description()
  File "/usr/share/mypaint/lib/document.py", line 225, in get_description
    cache_update_interval = CACHE_UPDATE_INTERVAL,
ValueError: Single '}' encountered in format string
INFO: lib.document: Using u'load_ora' to load u'/home/kaira/Desktop/Prints DA/witch kaira logo.ora' (kwargs={'feedback_cb': <function gtk_main_tick at 0x7fa3b18b06e0>, 'convert_to_srgb': True})
INFO: lib.document: load_ora: u'/home/kaira/Desktop/Prints DA/witch kaira logo.ora'
INFO: lib.document: 3.690s load_ora total
INFO: gui.filehandling: Loaded from u'/home/kaira/Desktop/Prints DA/witch kaira logo.ora'
INFO: lib.document: save_ora: u'/home/kaira/Desktop/Prints DA/.tmpsave.witch kaira logo.ora' (None, {'feedback_cb': <function gtk_main_tick at 0x7fa3b18b06e0>, 'save_srgb_chunks': True})
INFO: lib.document: 2.518s save_ora total
INFO: gui.filehandling: Saved to u'/home/kaira/Desktop/Prints DA/witch kaira logo.ora'
[xcb] Unknown sequence number while processing queue
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
[xcb] Aborting, sorry about that.
python2.7: ../../src/xcb_io.c:263: poll_for_event: Assertiva “!xcb_xlib_threads_sequence_lost” falhou.
Abortado
 
The programming error message:

```python
Mypaint version: 1.2.0+gitexport.f62444e
System information: Linux-4.19.0-17-amd64-x86_64-with-debian-10.10
Traceback (most recent call last):
  File "/usr/share/mypaint/gui/application.py", line 412, _at_application_start(self=<gui.application.Application object>, filenames=[], fullscreen=None)
                autosave_recovery = gui.autorecover.Presenter(self)
                autosave_recovery.run()
  variables: {'autosave_recovery.run': ('local', <bound method Presenter.run of <gui.autorecover.Presenter object at 0x7fc7003b4b10>>)}
  File "/usr/share/mypaint/gui/autorecover.py", line 114, run(self=<gui.autorecover.Presenter object>, no_autosaves_dialog=False)
                    thumb = lib.helpers.pixbuf_thumbnail(thumb, s, s, alpha=True)
                desc = autosave.get_description()
                assert isinstance(desc, unicode)
  variables: {'autosave.get_description': ('local', <bound method AutosaveInfo.get_description of AutosaveInfo(path=u'/home/kaira/.cache/mypaint/doc.nOgvQ4/autosave', last_modified=datetime.datetime(2021, 6, 27, 6, 10, 0, 78177), thumbnail=None, num_layers=0, unsaved_painting_time=0, width=0, height=0, valid=False, cache_in_use=False)>), 'desc': ('local', u'Backup atualizado 20h40m atr\xe1s\nTamanho: 4864\xd72816 pixels, Camadas: 71\nCont\xe9m  0s de pintura ainda n\xe3o salvos.')}
  File "/usr/share/mypaint/lib/document.py", line 225, get_description(self=AutosaveInfo(path=u'/home/kaira/.cache/mypaint/d...dth=0, height=0, valid=False, cache_in_use=False))
                ago = last_modif_ago_str,
                cache_update_interval = CACHE_UPDATE_INTERVAL,
            )
  variables: {'cache_update_interval': (None, []), 'CACHE_UPDATE_INTERVAL': ('global', 10)}
ValueError: Single '}' encountered in format string