Should I confront my kids’ dad about inappropriate behavior/language after a visit?

My kids’ dad was granted supervised visitation a couple weeks ago after not being around for all of my kids’ lives. He was abusive and used to publicly shame me any chance he had, even in court. But I thought things were okay once visits started. Awkward for sure, but civil. I notice that my daughter (2) seems hesitant to go whenever we get in the car. But she’s typically a clingy toddler and this/he is really new so I didn’t think anything of it. But today, when I picked them up, my three (4 in April) year old, he seemed just… weird… about being exchanged. Usually he gets excited to come home but this time he seemed really distant. His aunt (who is supervisor) was like “Oh he probably just doesn’t want to leave us the same way (daughter) doesn’t want to leave you”. I was like “uhh, ok, whatever then” and just took him home. But after we started driving, I was trying to talk to him and he all of a sudden goes “f*ck your mama”. At first I just told him not to say that and tried to change the subject. But he kept saying it - over and over and over. His dad mentioned to me the other day that he accidentally “slipped” and said a bad word in front of him but claims it was just that he sneezed too hard and said “fuck” but corrected himself to them. (Brought it up on his own accord). I texted him after pick up and said “is that the only time” and he says it is. But now I’m wondering if something is going on and my daughter being upset about leaving is a sign so he’s trying to cover it by “getting even”? Idk. Some people are saying “just document it”, others are saying I should bring this up to him and ask so he can’t say I’m just making it up later.