Kaya doesn’t seem to like Tenley very much atm
She doesn’t dislike the brat. Ten did save her life, after all. But Kay’s also seen how strong the girl is, so she’s wary of her. Not because she thinks Ten is inherently a bad person (although she did murder six people, something they will have to face no matter how justified it might have seemed at the time), but because she’s a kid and she knows that kid’s don’t always have the best control over their emotions. Kay and Jennifer don’t have much experience with children either, and all it would take is for Tenley to lose her temper for a seconds for her to do serious harm to someone, without necessarily even meaning to.
Of course, given all that, it may seem a little foolish to keep teasing and antagonising the girl. I guess that’s just how Kay shows her dissatisfaction about something. Of course, it’s also she shows satisfaction, just using a slightly different tone of voice.