You know my ex bounced back about six months post-D. Not a word out of his mouth about any regret about what he's done. Nasty ugly scene -- I had to kick him out of here and call the cops on him to get him out of here.
It probably is him trying to reconnect a bit. My weird ex does maintain more contact with the kids these days, which is probably good. I wouldn't doubt that there's something inside of him missing the kids because they're all grown and gone now -- and he has to see them on his terms. He doesn't seem to like that too much. Me -- I'm just happier than heck when they call or come by even though school and work commitments makes that not very frequent.
So...I'd just take it that he's trying to be nice to the kids and that's that. You are happy and whole and thriving. Last thing you need is to go down the path of "what ifs" letting him hook you back into his weirdness.
I don't know much about MLC--while I think my ex probably did go through some MLC stuff, I think the primary problem he had was an addiction/alcoholism issue. And I'm not a shrink. So to me, bad behavior is bad behavior!!! He was rude, nasty, crude, and mean. Why get back into his way when all that does is make everyone in his path feel miserable?