I ran into a website for work that would let you create a long password, but silently truncate it to 12 characters before saving. Mind boggling.

Blizzard/battle.net used to this (still does?), lol

This is the best. Especially when the password is being autotyped by the pw manager and so you never see the truncation and now have a bad pw saved in your manager. Alongside a restrictive password policy with no ui explaining what the policy is.

This happens on some HP printers too, the web interface lets you happily enter lengthy passwords, but doesn't bother telling you it truncated the entry at 16 or 12 characters.