Don't understand why now

Because douchebags like that cannot stand the fact that you've distanced yourself and now they are sucking up.

Why?

Ego.

You could go back to the behavior you had before and that guy would back off so fast and go back to the old behaviors. I've seen this plenty before. It's so predictable with guys like this. There is no deep seated secret feelings involved here. Just pure ego. And one could argue that this is a Libra behavior thing with the whole "omg someone dislikes me. I need to make sure there's no bad blood and will patch things over to keep the peace.

You should just observe with amusement and learn from what you're seeing. It's what I've done with guys like this. Behaviors can be very telling if you pay attention.