Just checked it one more time. Reloaded the game at 00:02 UTC to reset season quests (that old bug is still very annoying), rechecked that there is no keys on the ground (no notification after loading), opened spire, waited for 15 minutes (as I know that key spawns somewhere between 00:02 and 00:15), returned to the city, got notification about new key, clicked on the key and voila - it's bugged again.