App not starting when clicking on it, happens once in a long while

Is there someone who ever clicked on an app, it didn’t open, but then tried a second time and it worked?
It’s starting to annoy me, but it occurs once in a long while and I’m always caught of guard, so I can’t film it in order to file a bug.

The app in question is the Flatpak version of Firefox.
Is this a known issue?

Managed to get in video after trying multiple times.

https://bugs.kde.org/show_bug.cgi?id=495767