Thanks for the reply, @mutahhir.
I haven’t been able to reliably recreate the steps myself, so this is as much as I know.
I’m not using any FoldingText Plug-Ins, and it sounds like this is a rare situation. So my guess is it’s being caused by another app. I’m running some experiments to isolate that. No luck yet, but I’ll update this thread if I can find it.