I have been experimenting with various flow simulations for a heat exchanger assembly. Every time I try to re-open a previous assembly, the lids are displaced and it says "Cannot find bodies associated with this feature." , referring to the inlet volumetric flow that was placed in the inside face of the lids. I am unsure of why the lids would not be where they were previously mated. Does it have anything to do with having to rename the lids for each assembly? Any info would be greatly appreciated.