There has been a change to the way that holiday mode works. This is actually a change that we had implemented several months ago to avoid people "riding" holiday mode instead of using it for it's intended purpose of being on holiday and knowing you will miss turns.
When implemented the first time we introduce a bug that occasionally left a game sitting when it looked like all the players turns were submitted. In this case, one player actually had not submitted their turn and had holiday mode enabled. This player would then end up with a "mystery" missed turn. We have now fixed this bug and holiday mode will now work as follows:
When holiday mode is enabled you will not miss your turns. However, if you are the last missing turn and host is within 24 hours your turn will be marked as ready and host will run thereby not holding up the game. This will not result in any extra turns but will keep games running nicely during your absence. Be aware of this rule when choosing to enable holiday mode.
The maximum holiday mode period is still 3 weeks.