Is it possible that this has been happening already?
We’ve been trying to track down what we call a “progress tracking issue” where the user will go in, do some stuff in the course, close out, and the next time they come back, that progress has not been saved. This sounds very similar to what we’ve been experiencing, except we don’t have Chrome 80 and we’ve been dealing with this issue for over a year now.
It being attached to the user’s browser exit might explain how it is affecting some of our users but not others – but of course, how do you get it into their heads that they need to not use the browser exit button? We have it in text, in video, and remind them with almost every help call/email.