I've created a reusable item in Teamcenter. So when I've reused it with clone option and defined their dimensions the NX just "Save As" using original file and it losted my choice.
I attached a picture that explain how I setup the item. I prefered to used that because Family of Parts doesn't create drawing automatically and doesn't permit to change manually the expressions on insert.
Let me show you what happened. I attached two videos that explain better.
1 - REUSABLE_WITH_DRAWING.avi - Reusable item that contains drawing (I've using Master Part concept)
2 - REUSABLE_WITHOUT_DRAWING.avi
I just tested NX12.0.0 with Tc11.4 and the size did not reset at any time during the operation. Is this repeatable for you with all reuse components that have drawings?