Syntax error highlighting occasionally fails to refresh on individual files

In the last couple of days, I have noticed issues with QtCreators syntax error highlighting. I use QtCreator 4.8.2 on ubuntu 18.04 both at home and at work. Starting either yesterday or the day before, I have noticed on both machines that some syntax error highlights get stuck on a page along with the corresponding red right or yellow triangle in the line numbers... They persist long after the errors are provably fixed and I have successfully built and ran the code a number of times. It usually clears up after a "save all", but that has not been working here. To clarify, syntax error highlighting continues to work as expected everywhere else in the project (maybe even elsewhere on the same file?), but just a specific set of syntax error highlights persist in a particular file. 

I know there was an update to QtCreator recently, but I can't remember if these issues appeared in correspondence with the update... I am also working on totally unrelated projects at home and at work, so it can't be an issue in the project or settings that has suddenly appeared on both machines.

There is also another issue that started seemingly at the same time, but I can't be sure if it's related. I will link that just in case when I get around to creating a ticket for that.