Unified inbox widget doesn't show big inbox.

[magnetophon]

When I installed K-9 and first setup my mail, the widget was showing all mails, as expected.
Then I set the "Local folder size" to "all messages" and "Sync messages from" to "Any time (no limit)".

Expected behavior

All messages shown.

Actual behavior

No messages shown.

When I set a lower limit and reboot the widget works again.

Steps to reproduce

1. have a big inbox (in my case +/- 5000 mails, 300 unread)
2. set the "Local folder size" to "all messages"
3. set "Sync messages from" to "Any time (no limit)"
4. add "Unified inbox widget" to homescreen.

Environment

K-9 Mail version: 5.600

Android version: replicant 6 0003

Account type: IMAP

Please take some time to retrieve logs and attach them here:
My version of adb:
Android Debug Bridge version 1.0.40
Version 4986621
Installed as /nix/store/73zsiynckxkki5xxap7qk7r4laxp1g60-platform-tools-28.0.1/libexec/android-sdk/platform-tools/adb
does not recognize the --pid option.
I was not able to find out how to log just K-9.
Please update the wiki and I'll attach a log.