The code in question being in my common.js here (and on some other wikis) : https://en.wikipedia.org/wiki/User:ShakespeareFan00/common.js (currently commented)
being the code from https://en.wikipedia.org/wiki/Wikipedia:WikiProject_User_scripts/Scripts/WikiBreak_Enforcer
Sequence of actions taken:
1. Log into a a wiki with SUL, where the enforcer script is not active.
2. Navigate from that wiki back to English Wikipedia, or via a link a search engine.
3. Wait for the enforcer script to generate it's first message.
4. Click the acknowledgement in that message.
Expected behaviour:
Log out on the, and return to the main-page of the qiki in question per the intent of the script.
Observed behavior:
Log out does not seemingly occur, and an error page about using the UI provided logout page is generated. The script then regenerates the Wiki break enforcement notice. Acknowledging it again regenerates the error page and the enforcement notice in an apparently un-ending repeating cycle.