This way, it's no benefit to return from the 2nd OW space and there's a terrible monster waiting for you.
NEXT Turn: I have to combat the monster during movement!
Since I only don't have to fight the turn I return, but have to, the next turn or don't I ?
Yes, next turn you will have to fight the monster. You're only given a "free pass" on the turn you returned. You seem to understand that this turn has expired.