I've set a passcode lock in my Chrome browser on work PC, when this feature was added. Since then, twice my passcode weren't recognized and I had to log out. First time I thougt it's just me, who wrote it incorrectly. Second time this happend, i've checked the passcode i wrote couple of times (even tho it's not really complicated), and the app returned an error anyway. Unfortunately, I didn't notice any patterns, that could be connected to the problem.
If it's any help, I have a pass code on my phone app as well. But it's different, due to symbols limit (I've tried to apply the phone pass lock in web, no effect).
Telegram Web 1.48.2 Z, Chrome 102