Ozelots & Wolfs summoned by a command can't sit

Sometimes when I summon Ozelots and Wolfs using a /summon command like

/summon Ozelot ~ ~ ~ {CatType:2,Tame:1,Sitting:1}

, they don't sit, and sometimes they sit but the entity animation is like they're standing. When I quit the game and launch it again, the cat (the dog) is now sitting.