A user sets up an account on 10/1 with email email@example.com. On 10/5 a staff member changes the user’s primary CRM email to firstname.lastname@example.org. The user goes to BBIS to reset their password on 10/30 and they enter email@example.com. They will receive the forgotten password reset email at firstname.lastname@example.org but when they try to enter a new password it says the user doesn’t exist or has been deleted. It seems like when you click the Submit button to send the email it switches the email in the BBIS user account from email@example.com to firstname.lastname@example.org. The email@example.com is in the url of the reset link and it can’t find it anymore.
Download and install the latest patch, which contains all fixes from previous patches. If you are running an older version, download and install the latest version and then the patch.