When a user chooses repeating donations and enters the number of months, at the time they click the DONATE button the number sometimes changes to 1, turning the repeating donation into a single donation. It doesn't matter what number the user has entered, 1 digit or 2.
This could mean a loss of money if the user doesn't catch the bug.
This is an intermittent problem — doesn't happen every time. I'm using Firefox 7.0 beta.