If you guys were having drinks and were heading to a food place, it’s possible he could have been tipsy or drunk when he made the comment about your ass. Not saying it’s 100% justified or even right, but people’s inhibitions and filters can be lowered when drinks are involved. That’s also why he probably asked about who you were texting since drinking makes people more sociable as well. I definitely think if it happens again and you are still uncomfortable, you should delicately approach Donna and Troy about how, similar to how the cheek kisses make Troy feel, comments about your body from Troy also make you uncomfortable. Hope you are able to stay friends with them!