Nice hack.
Running Version 1.8 on 3.67.
Recently installed and ran the Ezbounce on about 3500 members. My users aren't getting put into their original usergroup when they are updating their email address.

They are staying in the group they were moved too when I clicked the ezbounce link.
No reactivation email is sent. I assume it's only sent if Verify Email address in Registration is on. I usually have this off. Turned it on temporarily. Tested, got the reverification email, clicked, but still didn't set the usergroup to the original.
EZ Bounce Management - construct code mail_send
EZ Bounce Management - update values register_activate_process
Changed these hooks execution order from 10 to 1. Didn't make any difference.
As far as I can see I have no other mods using these hooks so there is no interference there.
Any idea what could be going on? Please help.