Weird throw up(green tree python)

[Math020]

Hi guys I'm new on this forum.
My friend told me is the best forum for reptile

So here's the issue

I loved his Green Tree Python for about four years.
Always eat well seems fine, but about three years ago he stopped eating for about 2 1/2 months.I catch him make squishy sound seems like he's was throwing up. Bringing to the vet but with no poops because obviously he was not eating that seems to say it was nothing.

So for the past 2 1/2 years eve never skip a meal and the first time was 12 days ago because he was in shedding.

Ease a regular eater and always poop between 8 to 10 days after he eat.

So now I catch him today doing the same thing as you did 2 1/2 years ago

He threw up and pooped liquid and forcing his body like crazy with the empty stomach.

He don't do that usually. I cut him like I said 4 time and is always when his stomach was completely empty.

Thanks for your help I really appreciate any commentS
Here's the video on YouTube's of my snake





Five minute after what happened it seems really fine