Changes in an applied physical material are not automatically picked up by the PHAT mass properties display. A manual refresh is required for the display to update to the correct values.
Adjusting a body's COM offset does not effect the location of the drawn PHAT mass properties display.
Open a skeletal mesh in PHAT.
In the view-port under Character options, enable Mass Properties.
Adjust a body's Center of Mass Offset, notice how the displayed location of its mass property doesn't change.
Apply a physical material to a body.
Adjust the material's Density or Raise Mass to Power.
Notice how the mass property does not change.
Refresh the properties by Enabling and Disabling the body's MassInKg.
Notice how the mass property has changed.
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-82038 in the post.