It happens to me after snap updates firefox and removes the old version the icon was created from. I had a look at desktop file and while Exec property is not version specific:
Exec=env BAMF_DESKTOP_FILE_HINT=/var/lib/snapd/desktop/applications/firefox_firefox.desktop /snap/bin/firefox %u
The Icon is:
Icon=/snap/firefox/1406/default256.png
It happens to me after snap updates firefox and removes the old version the icon was created from. I had a look at desktop file and while Exec property is not version specific: FILE_HINT= /var/lib/ snapd/desktop/ applications/ firefox_ firefox. desktop /snap/bin/firefox %u firefox/ 1406/default256 .png
Exec=env BAMF_DESKTOP_
The Icon is:
Icon=/snap/
Maybe use current symlink?