I have solved the problem.
This problem is related to desktop shortcuts I requested for help in another thread and in files:
~/.local/share/applications/libreoffice_calc.desktop ~/.local/share/applications/libreoffice_writer.desktop
I have now notices that I have had “fixed” paths for Icons parameter in them:
/snap/libreoffice/208/usr/share/icons/hicolor/256x256/apps/libreoffice7.1-calc.png
and now when LibreOffice updated to new snap release, new path was created:
/snap/libreoffice/213/usr/share/icons/hicolor/256x256/apps/libreoffice7.1-calc.png
It looks to me that 208 and 213 are snap revision numbers and this revision numbers are not smart to have in any paths, because when new snap revision is released this number changes. Now in first two flies in this post, I have changed the path of Icon parameter to:
/snap/libreoffice/current/usr/share/icons/hicolor/256x256/apps/libreoffice7.1-calc.png
and this solved my problem.