My soon to be ex has done this a few times. He normalises it. It doesn't sit well with me at all and at times I have serious trust issues leaving him with the children at all. I have screamed "shut the f up" silently into my hands out of earshot of kids when they are really pushing me. He has not really been with them long enough to be pushed like this.
There is a lot of issues which is why he has been asked to leave. I am trying to keep it amicable as possible but this among other things really makes me rethink how to go about co parenting.