Using Version 2023 (1013) 64-bit on Windows 11

Trying to get rid of a persistent part marker. I've tried everything, including "return to factory settings" and restarts, but I can't get rid of an unwanted part marker that keeps showing up in the middle of a phrase.

Sequencing through the series of part options to the "blank" marker makes it go away temporarily, but as soon as I hit a "Play" button, it reappears. I can eliminate the drum fill, of course, but how do I get rid of this bogus part marker?