I've had this before at a University I used to attend. I had a password with either a % or a & and I found I couldn't log into one specific system. I changed my password to a different one, but still had one of those special characters. I was curious and tried a more "basic" password and I was able to get in. The system just wouldn't accept certain characters in your password. The main University password manager did disallow certain special characters, but clearly not enough of them.

It never makes you feel very confident in an institutions security when they can't even figure out how to get a username/password to work properly on their systems.