I just tested and it still works fine for me. The only thing I can think of for you to check is that previously there was a bug in the mp_Users_Login or mp_Users_LoginByEmail stored procedure where the password variable was declared as nvarchar(20) when it should be nvarchar(128) so it was truncating the password on the way in and login would fail. But this has been fixed in recent releases so I can't think of why this problem occurs for you. I would look at those procedures though in case they somehow did not get corrected in your installation.
Hope it helps,