Pack and go breaks my external references (SW 2019)

I tried to use the pack and go feature in solidworks to make an exact copy of my assembly. However, when i go inside the "new" assembly that i've created,i have a question mark next to the majority my parts in the tree. When i right click on a part and select external references, all of my external references are now indeed out of context. In the original assembly, i do not have any parts that are out of context.

I hope you guys can help me out on this​​​​​​​


EDIT : more details that created my problem : i actually formed a new sub-assembly from the "new" assembly that was copied. Tbh, i think that's a one time bug, because i did a similar manipulation with the same assembly before and it worked.
However, SW does loose the external references (with the parts that are not in the sub-assembly), when i form a new subassembly.