I have a question regarding the time a Pokémon can stay in a gym. I haven't found anything regarding this topic, so if this is a dupe I'm sorry.
Some background: I've been on vacation in Croatia and there was a gym on an island which isn't frequented by many players. I've battled it and put one of my Pokémon in.
This was 12 days ago and it hasn't returned yet :(...
Now to my actual question: Will Pokémon return from gyms after some time or do I have to wait until someone defeats it?