Yes, I've been having a bit of a problem too, but have a solution, or at least a work around:
I use Firefox as my browser, so this may not apply, but may be worth a try... When Family Search starts "acting up" I go to the browser settings page, and under Privacy, Cookies & Site Data, I select "Manage Data..."
I then have the option to delete cookies for selected websites. I only choose Family Search, and delete their cookies.
When I return to editing, I have to log into Family Search again, since deleting cookies logs you out. Then it all works great! (Until a few days, or a few weeks later!)
Let me know if this works for you!