Short story what is happening here:

I copy an assembly, including its parts.  (its not an Pack&Go copy, its a DriveWorks copy, so i can not change the way of copying)

The boss extrude of this part has its EndCondition set to another part of the assembly.  → Up To Surface - EndCondition

The boss extrude looses the reference surface after copying    (Problem Starts here!)

→ When i try to set the Surface for the