Something I’ve noticed recently that wasn’t happening before…
(this is with pre-set scenarios, I assume it would be the same if a “New” game was involved).
Online game comes to an end.
One of the players closes the old game opens a one.
Everyone (or at the very least, observers) syncs to the new game automatically, without closing the existing game.
Result: The players affected see the new game overlaid on the old one.
Workaround: Sync’g to the player who opened the new game will fix the problem.