So you can still have your turns skipped for whatever reason. I'm really not sure what is causing it anymore, before we thought it was firespitters and while that did lower the number of DOUBLE TURN stuff, we're still having major cases of turn-arrow skipping.
I'll post with more details when/if I find them.
How(?) to reproduce the problem:
1. End a Battle
2. If you still have the turn timer icon, start another battle while it's still there.
3. The old turn timer will continue to countdown as normal, and end your turn if it ends during it.
Notes: And if you manage to finish your turn before that, the newly applied turn will count down as well and start the cycle all over again.
Workaround:
Don't start a new battle until the turn timer icon has timed out
I find this happens often while grinding in dungeons or the arena, since people have little to no time in between each fight.
I have noticed the turn arrow not dissapearing even mid fight and when the turn timer would expire (no matter whos turn it actualy was) it skipped my turn.
This issue is probably related to ending turn passes the turn to someone else, but does not end it for you. Aside from removing the whole menu until you get "called" by a new turn again