The title pretty much sums it up. I must have modified the skeleton, I do remember there was something in the spine that I might have re-parented, but it doesn’t appear to actually be different! Maybe I’m just having a hard time identifying the difference here (and ofc regenerating bones ruins the whole thing) but are you guys able to spot the difference? Or maybe know of a workaround to this problem without having to recreate my anim blueprint from scratch? Thank you for any and all your time. Note: I manually drew lines to see differences and the one I spotted was actually because i didn’t hit the drop down for the index2 
well, before anyone tries to help, I merely bit the bullet and recreated the anim bp and all the blend spaces 
Coming back to add a little bit more clarifying info as I have become stronger with my brain:
- OriginalBlenderFile → 1stExportedFbx → Import Into NewBlenderFile → 2nd ExportedFbx
*Any skeletal meshes generated from 1stExportedFbx within UE5 will never (even if unmodified) be recognized by UE5 as the the same as the 2ndExportedFbx - All fbx files need to be exported by the same original .blend file (and of course, the bone hirearchy needs to be unmodified)