My ball python just bit me very calmly?

This just happened so im coming in here to see if anyone has had this happen before. I picked up my ball python like i usually do (i don't handle them a lot mostly just to check up on stuck sheds etc.) he's always been the type to just stay in my hand chilling not much slithering around, then very slowly and calmly turn to my palm and opens his mouth. It was so slow i had time to readjust my grip on him to not let him fall while removing my hand and he barelly stuck on me just a single pinch and stopped.

I knew it would happen at some point but he did it in such a weird manner so i'm wondering if ya'll know why they do this. My assumptions is when i got to the room he was peaking out of his hide and got startled when he saw me, so he was already nervous when i went to pick him up and requested to be let down. It also can't be a feeding bite cuz he ate last thursday.

It scared me at first but not enough to stop me from handling him for today i will give him space tho.