Maximum number of characters when creating passphrase

I have installed gpg4win 3.1.11 on two computers in our small nonprofit organization and have successfully sent a couple of encrypted test messages from Outlook. Thus far I have found the differences between the online instructions and the current version of the software fairly easy to understand.
My only question so far is that in two different browsers, I appear to be limited to passphrases of 13 or 14 characters during initial setup of a certificate. If I attempt to enter more, the passphrase gets rejected.
Am I doing something wrong, or is this a known bug? Would it be possible to use the change password feature to increase the number of characters?
I am greatly appreciative of the efforts of Intevation, the German government, and volunteers who contribute to this project. It will help us protect personal data while minimizing our administrative costs.