Floating relationship behavior after purge

Noticed this (in my mind) unexpected behavior (tested in aras 11SP15 and aras 12SP18):

Two items (parent and child) related with a relation with float behavior.
Create a new generation of the parent and the new current item has a float relation to child and
the old parent items relation to the child is set to hard_fixed.

If i now purge the current generation of the parent, the previous generation is set to current but the relationship is still set to hard_fixed.

Is this the intended functionality ? 

/Regards Johan R.