Physics Asset Broken 4.16

I had a working physics asset for my VR game in UE 4.14
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HOWEVER - as soon as I take it into 4.16, it breaks.

The physics asset performs as expected if the root is “simulated”

HOWEVER - as soon as I set the root to “Kinematic,” one of the bones snaps to the root’s origin (regardless of being locked)

THEN - if I delete the body on the working bone, the broken one works if it’s the only simulated one:

I also tried having “in between” bones between the root and the end bones - however - whether those are kinematic or simulated, it causes REALLY weird issues like one of the bones flying away completely:

Does anyone know what’s causing this? Or why it worked in 4.14 but not 4.16?

I tried:

  • re-rigging multiple ways
  • re-exporting the FBX with different file names
  • importing the FBX into different sub-folders
  • messing with every setting on the bodies and constraints
  • disabling/enabling collisions on individual and all bones
  • re-doing the bodies and constraints manually

I’m really at a complete loss as to what’s going on here - I feel like I’ve tried everything. Is this just a 4.16 bug?

I’m exporting from Blender - all of the transforms are applied.