I reported this as a bug months ago and got an acknowledgement for it.
I initially thought it was just from being staggered, but later learned it was taking any damage at all, which makes it seem like it isn’t intended behavior.
I only thought it was a bug because I don’t remember this ever happening to me using a Force Sword or Zealot/Ogryn mauls/hammers.
No idea if it will get fixed and didn’t get a reply saying it was intended behavior.