Thank you for your quick answer.
The growlithe reappeared but I miss a Mr Mime now. I think it has something to do with the Abra I caught which vanished and left me with two identical Farfetch'd. The Abra keeps reappearing but then a Pokemon from my team is missing. When my team is complete, the Abra is missing.
EDIT: This morning, all the Pokemon of my team were there and the Abra was in store. When I logged in now, the Mr Mime was gone again, but a Ponyta was on its place.
These are the two identical Farfetch'd and the Abra: