In this answer, I used \tikzmark to mark the extent of a typeset piece of text, so I could draw changebars next to it. But it initially seemed that the changebars "disappear" with math-mode content. ...
I have a lot of problems lately with macros expanding (or not expanding) at unexpected times, so thought I was having a related problem here. But, in this case, things are working as I want outside of ...