Why wasn't this question removed automatically from the HNQ list?

Question

From previous discussions, I've come to understand that questions with MathJax in the title cannot become hot network questions, and that editing a title to include MathJax should boot the question off the list. The reason for this, as I understand it, is that not every SE site employs MathJax, and so, such titles will not display properly.

Now, this question began with a MathJax-free title, after which it became a hot network question. According to the timeline for this post, this occurred on the 3rd of June, at 14:03. The title was then edited to include MathJax 43 minutes later. Four and a half hours later, a mod removed it manually from the HNQ list.

I'm just curious: why did a mod have to remove this question? Am I wrong in my understanding of how MathJax and the HNQ interact? What did this question look like on the HNQ, on the sites that don't use MathJax, in those four and a half hours?

EDIT: The following SEDE inquiries come from the ever-helpful Martin Sleziak:

1. Questions which were in the HNQ list and have a dollar in the title
2. Questions which were removed from the HNQ list and have a dollar in the title
3. Questions removed from HNQ after dollar was added
4. Questions where dollar was removed after the removal by the mod

He says,

These queries probably won't find all occurrences - there may have been several edits where \$ was repeatedly added/removed and then again added/removed. These queries look at the first addition/removal of "\$" in the revision history.

Answer 1

MathJax titles remove questions from the HNQ. However, after some incidents with users rolling back MathJax improvements to get questions back into the HNQ list, I've developed a habit of using the moderator powers to make sure that there is no point in making that reversal.

It is a generally unnecessary step, like shooting a dead horse in the head, but we live in a world where sometimes the horse becomes a zombie, so it's good to be safe. Sometimes.