Issues with external reference features - trying to break ref. delete the feature.

Whenever I copy a surface in an assembly with 'Knit Surface' to a new part, I can't disconnect it via the 'List external Ref. --> Break all'
when doing so (with or without 'insert the original...') it delete the surface and doesn't keep it disconnected.
From the description, I understand that it suppose to keep the feature (surface / sketch) like an Imported geometry.
I can freeze it, but then I won't be able to add future references and someone may accidentally unlock them later on.

SolidworksParts And Features