Incorrect icons on panel for some running flatpak applications

[letuxmasque]

 * Cinnamon version 4.8.6
 * Distribution - Linux Mint 20.1 Cinnamon, LMDE 4

Issue
Icons are incorrect on panels for running LibreOffice and Calibre flatpak applications.
With LibreOffice, on Linux Mint 20.1, the icon is the one for LibreOffice Impress and not this for LibreOffice Writter and on LMDE 4, the icon is this for LibreOffice and not this for LibreOffice Writter.
With Calibre, the icon is the one for Calibre Viewer, not for Calibre.
And when you are running by exemple LibreOffice Writter and LibreOffice Calc, both are grouped together in the same icon on the panel. Same behaviour with Calibre and Calibre Viewer.

Examples:

• with Linux Mint 20.1 and LibreOffice Writter flatpak application:

• with Linux Mint 20.1 and LibreOffice Calc & LibreOffice Writter flatpak applications:

• with Linux Mint 20.1 and Calibre & Calibre Viewer flatpak applications:

• with LMDE 4 and LibreOffice flatpak applications:

Steps to reproduce
Install LibreOffice from the flathub
Run LibreOffice Writter
Look at the icon on the panel

or install Calibre from the flathub
run Calibre
Look at the icon on the panel

Expected behaviour
Examples:

• with Linux Mint 20 Cinnamon and LibreOffice Calc & Writter flatpak applications:

• with Linux Mint 20 Cinnamon and Calibre & Calibre Viewer flatpak applications:

[NerdsMaxx]

I have this same problem. Please someone fix this! I just installed linux mint. Please🙏

[heroldn]

Ditto, please fix this as soon as reasonable. Very annoying especially when combined with the window re-ordering bug!