Marking shows as unwatched and 24 hours later they go back to watched

I know how to mark shows as unwatched but within the past month or so the shows no longer stay “unwatched”.   Today I noticed that if I mark a show unwatched on one tv the other tv still shows it as watched.  I have gone to both TVs and have marked the shows as unwatched.  I hope it works because I have refreshed the boxes and have done a system reset.  Both of those options haven’t worked.  It’s not just one channel this is happening on.  Any other options to try?  Other people in the household are confused about where they are in a series but I’ve watched ahead of them.