How’s the work on this bug progressing? It seems to be getting worse. It’s very annoying. 
Don’t know if it was the whole solution, but after putting Roon in my list of apps that cannot be switched off in the background (on my Android) it seems I do not have this problem anymore, also not on my Macbook. Rather strange to assume that my Android-app was messing around with indexes on other devices. Maybe it is worth a try 
I’m stuck on Apple devices. Would the iOS equivalent be “background app refresh”? Roon does not appear on the list of apps in that selection screen.
I reported this in the recent beta trial. No response from Roon.