@kugiigi
correct, the pin entry does not need any confirmation after enough digits are entered. So once the screen is on any random touches on the numpad will lead to a string of login attempts.
@lduboeuf
I have both the greeter and the launcher disabled. it's possible that I failed to enter the pin on the full keyboard as I was a bit rushed. 🤷
In any case, given that the bootloader needs to stay unlocked and UT not does support encrypting the home partition(?), I don't think the possible limit bypass by pulling the battery is a large security issue, but it was also not the expected behaviour 👋