Just as the subject says - Bridge batch rename feature is buggy to the point of unusable. Even after resetting prefs as per the ctrl+alt+shft thing when opening Bridge. Cheers. 🙂
I have the same problem with Bridge 12.0.1. Deleting the preferences did not solve it. I have now installed Bridge 12.0 again and it works with this version.
I've had to go back to Bridge 11, which is not ideal. I have to use 11 to batch rename, and the latest version for image processor. It's a work around, but I can't say I'm happy about it.