I raise too in that situation. I don't see a flush being played like this. Maybe someone's holding the Ad, but I don't see someone working a flush like that. In my opinion, it looks like you got one person drawing to a flush at worst, the other one's sitting on a king.

I'm raising to get what i see as a flush draw out, probably checking the turn to hope the king improves and raising a bet / betting the river. If either one calls another raise (or both do), I fold to a bet and let them go at it (unless the board pairs).