22 hours ago
In the applications menu, Firefox Web Browser appears with the correct name.
When launching, it's name changes to just Firefox, and its icon appears as a greyscale version, instead of the usual symbolic version.
This is not particularly annoying - just a minor inconsistency, but it means that the running Firefox icon is separate to the pinned icon.
I did recently install Firefox inside wine, which added a new shortcut, but I don't see how it could conflict.
The last time I encountered this issue was in Windows 7 and with Google Chrome, so it's been a while.
I have tried reinstalling Firefox, but that didn't help.
If I favourite Firefox instead of Firefox Web Browser, the icon won't launch anything. If I favourite Firefox Web Browser, it will launch as a separate icon.
There may have been some background updates (I kept automatic updates on for security reasons - I don't usually bother to install them otherwise).
I can probably manage this small issue, it just may be a bit hard to get used to having the icon in two different places. I don't want to pin them next to each other, because that looks even weirder - I'm already used to some non-native apps having this issue.
Edit: It seems to be related to Wine, as when launching from the new logo, Wine starts up, before closing again.
9 hours ago
It didn't take me long to realise that this was directly related to Wine.
I hid the duplicate version of Firefox in my menu, but Firefox Web Browser must have picked up the other desktop file.
I fixed this by removing "~/.local/share/applications/Firefox.desktop" and "~/.local/share/applications/wine/Programs/Firefox.desktop".
If this happens to you, don't use Wine if the software is already available in Linux. I was just doing this for fun to see what happened. If you do want to do this, make sure to remove the desktop files properly, otherwise you may encounter issues.
I have had similar issues with desktop files, such as adding a Java-based application to my menu, and all Java processes appearing with the same icon in System Monitor.