Is this specifically happening when the text is currently in preformatted/fixed width style (as shown in the screenshot)? Or under certain other conditions?
I believe I found the culprit. A couple paragraphs above I had a block of normal text that had its last word pre-formatted using these back ticks (`).
I tried a couple things but I ultimately had to delete forward starting just before that escaped word. After that I was able to format everything properly, including that one escaped word.