Multiple Ozelot's spawned via Command Block

I've playing with command blocks, and I've noticed a strange behaviour with command:

/summon Ozelot ~ ~1 122

This command spawns an Ozelot, but strange is that it sometimes spawns 3 of them, 1 adult Ozelot, and 2 kitties.
I believe coordinates doesn't matter, since I've tested it with 2 different coords.