Comment by throwawayboise

Supermicro BMC passwords do that. Recently (i.e. this year) I set up a bunch of servers and was setting the BMC password to a known value.

Apparently there is a limit of 20 characters for the password. The password I set was 21 characters (which was accepted without error).

When I tried to log in with this password, the login was rejected.

However if I log in with just the first 20 characters of the password, it works.