Unexpected Timeline Audio Issues

We are hearing about some unexpected timeline behavior in our modules from our learners.  They seem related, even though there is somewhat opposite presentations of the issue.  Our courses are built in Articulate Storyline 360, we have the settings within our scorms to require the learner to watch the whole slide before allowing them to click on the next button.  The learners are reporting that the timeline stops progressing but the audio or the video still continues to run.  Then they are left with a long period of time to wait before the timeline catches up and allows them to continue.  We just started hearing about this in the past week or two.  I would expect that the module would either stop playing completely if it was running in the background, or it would continue playing correctly if it was running in the background, but not a little of both.  I can replicate this on my end, to some extent, if I try to play the module in the background.  For instance, if I start it in one browser tab and open another tab within that same instance of the browser the timeline stops progressing until I return to the tab that the module is in.  But the timeline progresses as I would expect if I have a second instance of the browser open and am working in that second instance of the browser as long as the window that the module is playing in is visible on the screen in the first browser instance. They are reporting that the timeline isn’t progressing as it should even if they keep the module open, front and center, and the only thing running.  This particular customer was able to see a more predictable behavior when he switched to his home computer that didn’t have a VPN or a web proxy. Another user reported that they noticed on a couple instances that audio stops completely while the video progress continues.They can replicate it on Chrome by running the video as per normal, clicking off tab, and then returning to the video. I cannot replicate this behavior of the audio and video getting out of sync. They report that the issue clears up if you go to the previous section and go back and resume where they left off.