My first thought on reading the OP was "does it really matter? It's not the worse thing, and if they otherwise have a loving relationship, let them sort it out between them".
However, thinking about it a bit more, it would be something that would bother me if I was in the OP's shoes.
When Ii was a child and teenager, my otherwise loving mother used to 'tease' me- just what she saw as gentle mocking if I got too big for my boots, or was a bit daft about something. She said that she did this because I was an only child and did not have siblings to tease me.
Unfortunately, it didn't really work. As a child, I did not have the vocal armoury to respond in kind. Also, it is not the sort of approach that squares with bringing up your child to be respectful of, and not cheeky to adults. I remember vividly one time when I was so frustrated with her teasing that I kicked her up the bum. We were both shocked, but I do remember my instinctive thought was "well, what does she expect?".
Sadly, all it taught me was not to answer back or defend myself when people were mean to me, and I think directly contributed to putting up with years of bullying in secondary school.
So, if your DP is happy for your daughter to tell him to piss off if he is mean to her, or to give as good as she gets when he makes a mistake, then let him continue. If he doesn't expect to have a relationship with her that puts him on a level with her peers, he needs to stop.