This is not uncommon. Many peices of software, whether they be BIOS or whatever can accept input larger than the field. Usually the entry is just truncated, but occasionally with crapware, like what I have to fix at work, the entry is lost. I'm guessing that the password field is 8 charachters, standard for BIOS's. The first 8 you input go through, nothing afterword. There is almost always an option to have the password protection just for CMOS settings, or for the system itself.