I am playing in my realm with my partner, we both have several cats and are seated at our base, we were thousands of blocks away , I started mining down in a savanna and both of our cats suddenly spawned next to us, note: I am playing on PC but my partner in an Android Tablet.
Seed: -2415277831574304761
World is attached
Update: I just came back to my base and several cats have disappeared, all were seated.
Coordinates: -236, 1050