Update to this:
While this works for some hair (Head), it does not really work for other hair like Eyebrows or eyelashes.
The reason for that is that Rigid disables the Groom from moving with the skin.
So for eyelashes to move with the eyelid (eyelid opens / closes), the binding type has to be Skin.
However, that leads to the groom to lag.
Sadly, Epic Games has closed my bug ticket on this 