With a video evidence, I can't see why someone wouldn't consider it a bug. If there wasn't something wrong, editing the highlight to make it larger also wouldn't work, but it did. Environment, user data and a lot of other things may interfere on reproduction. It can work fine on your phone and still be a bug that happens on others. And it's very easy to get rid of this, so it may be the reason why people doesn't report. Also, people rarely report bugs. I just removed the text highlighted and wrote it again to do so. I'm not reporting here because I need any help, but because the development team must know about it. Easily bypassable bug is still a bug.
Environment: Samsung S10+, Android 10