For password fields, some versions of BlackBerryOS automatically capitalize the first letter of the password. But other versions of BlackBerryOS do not.
So try both methods -- try typing the password normally -- If not, then try typing the first letter of the password and backspacing, then typing the password.
My 22.214.171.124 BlackBerry does it properly -- it avoids capitalizing the first letter of a password field. That's the way it should be for password fields!