Help with upper back pain and stiffness when inverting

TL;DR: I'm experiencing pain when inverting that doesn't seem to stem from the usual back weakness/shoulder engaging/etc. and I'm looking for other culprits.

Hey there, So title is pretty self-explanatory, but I need to give some background - I'm a beginner to pole and I'm about six months in. I have a very classic situation on my hands that I have found multiple web results and feedback, both in the sub reddit and elsewhere.

I experience sudden onset, deep, moderate upper back pain, in the area between my (invert side) shoulder blade and spine upon coming down from an invert and it has a certain stiffness that lingers around for a couple of hours- it very clearly feels like a strain and I am pretty sure it is one. I'm now taking it easy and resting, NSAI's and ice packs as well as foam rolling (WHICH IS GODSEND)

My actual problem is that none of the usual reasons for it apply to me: - I'm new to pole but I have been strength training for years so weak back and upper body is not the case - I regularly do sets on sets of 3-4 consecutive pull ups, and my One rep MAX on the lat pull down is 72kg. (I'm 65kg/~140ish lbs). - Scapula activation and shoulder engagement are not a problem for me because of my background in weight training. - I'd say I warm up sufficiently - Mind you my core is not the strongest but it's good enough to start an invert without kicking, I do bend my legs and tuck. - The only culprit I can think of if this: When I started inverting I was really keeping the pole in my armpit for security. So my legs would be going up but my torso wouldn't be tipping back to allow for the movement, which I think probably put strain on my rhomboids/lower traps. Now, I don't do this anymore, I consciously relax and let myself fall a little so my back remains fairly straight rather than scrunched, but the pain persists.

What do you think my problem is? What can I further do to correct myself? What could be causing it, that isn't the usual? Should I just give it more time to rest?

Should I put up a video of my invert technique to discuss?

Thank you all. :(