For several years now my groups have experienced the same issue. If a GM adds players to the turn order because of a combat say, and then resolves the combat, and then moves the players/game to a new page the following happens: The Turn Order clears and becomes empty for the Players. The Turn Order remains including player tokens for the GM, and the player consequently can't add players to the turn order again since they are already there. The fix during play is that once the GM is reminded of this weird Desync Bug, they should delete the turn order completely and readd everything each time they change pages. This problem has persisted for as long as I have been on roll20 and I don't know why, since it SEEMS like it would be really easy to fix in the greater scheme of things. Having a Turn Order that gives the same info to everyone should be pretty easy to do. But I thought for sure Roll20 knew about it and would fix it a year ago, so I didn't make a report and I guess at this point I have to assume that some how no one else knows about this?