I may be totally wrong here but I ‘think’ I am seeing something new going on with retention of ‘mon in a gym. Earlier today I had a ‘mon kicked out of a gym – nothing new there but when I looked at the gym the other ‘mons that were there with me were still there (and only those – nobody new) – seemed strange – why would someone kick out one mon without the others (and they are all low CP).
That got me wondering and I have been monitoring gyms in the area and I have seen two more examples were a single low CP mon has disappeared from a Gym – at the moment not seeing any great reason for this – I wondered if it was a new 24 hour kick out (mine was at about 24 hours or thereabouts) but I see other mons at over the 24 hours – the others I have seen ‘disappear’ from the gyms (again no change of team and no extra mons) have all been very low on CP.
It may just be co-incidence and there is some joker out there just sniping single mons out of gyms but first time I have noticed this kind of behaviour.
As the person who enters the gym, it has happened to me two or three times… I was there to fight down the Gym, but after the first fight I have received an important call, so was inable to stay more time and go away…
It was not nice for the first fight I won, but there are more important things in life than PoGo
Just not something I have seen actually happen before and all of a sudden I have had it happen to me and two other gyms I have monitored – hey ho – probably just me being hopeful some change is gonna come!
My hypothesis is that your Pokémon returned from the gym naturally (restructuring the gym) because of losing all their motivation. This is something I have never seen, but if the pokemon was PC low and stay several hours without feeding it is the only eplication I can think of. Again it is only a hypothesis.