Sorry for the confusion, that was my bad, that’s just my Linux wired brain kicking in while typing. Of course it is LIBRARY_PATH, and the problem is LIBRARY_PATH not being set when launching from QuickLaunch. I updated my posting above.
Anyway, back to topic: LIBRARY_PATH really should be set, and I don’t fully understand how this works at all in other cases.
EDIT: And I also just confirmed experimentally what was already suspected: When I launch QuickLaunch from tracker everything works, only from Shortcuts things fail due to missing environment.