I’ll throw in my 2 cents here too.
If you need that physics asset for other stuff here’s what I did.
I made a duplicate of the skeletal mesh and gave it the second physics asset (the one with just the head), and my actual mesh has the proper physics asset with all the physics bodies.
I have my actual skeletal mesh just there as a normal component in the blueprint editor, and I have that second duplicate version as its child. Then I parented all the groom components to that child mesh and made the mesh invisible by changing all of its materials to a simple unlit masked material with opacity set to 0 and unchecked cast shadows (when I unchecked visible in mesh rendering settings the hair glitched again, that’s why all that hassle with the materials is needed)
So, now, if you want to animate the mesh and do stuff with it, just do it on both meshes, and it should be alright.
It’s not a pretty workaround, but it works, so unless Epic fixes this, it’s the only way for now.