I'm using Trac 0.11.7 with AccountManagerPlugin r10594 with some fixes for issues detailed in #9091 and #9092. After a user registers, then logs in, he/she is greeted with a message to verify his/her email address.
The verification notification contains href html which I can't be more specific about because the anti-spam parts of this trac instance keep flagging it and ditching all the details I've written up forcing me to write up the bug again from scratch. Probably not your fault, but completely infuriating. Additionally c r e d i t s flags the system and that shows up in Python repl output.
Anyhow, the problem is around line 847 in web_ui.py in r10594.