[Zubersoft]

This one is going to be incredibly difficult to figure out. I'll run some tests on the two Chromebook devices I have to see if I can reproduce it, but if it's going to take hours of usage to reproduce the problem, that definitely will make it harder to test out any changes I make. I also don't know if it's an easy with the OS, with MobileSheets, or some kind of interaction between the two. The only changes that have been made recently that come to mind are the changes I had to make for the status bar and navigation bar on newer versions of Android. I'm not sure if that's related in any way, but you can try turning off fullscreen mode, unchecking the options to hide/dim the navigation bar, using the app for hours and seeing if the problem occurs. 

It's also possible something has changed in ChromeOS itself that is now causing this issue. That will be hard to determine as well.

Mike