Hi @JTy1
Thanks for posting and welcome to the Fusion 360 community! I am sorry to see that you have experienced this issue with the new Eagle/Fusion 360 PCB sync tools in Fusion 360.
The behavior your are experiencing in which the link to x-referenced designs in an assembly are lost when a PCB is pushed back to Fusion after edits in Eagle and are afterwards shown as "unresolved components" is due to a bug that has been logged with the Eagle development team as FUS-34925. This issue was brought up in this Forum thread and the ticket for the development team has been marked with the highest priority.
Unfortunately we do not currently have a workaround for this behavior. You may be able to reinsert the linked components, but I cannot guarantee that this issue will not occur again in the same file. Has the model of any of the previously linked components been changed by the loss of the links? If not, you could rename them back to their original names and work with them in the existing file (with no linked components).
Please let me know if you have any questions! We appreciate you bringing this to our attention.
Paul Clauss
Product Support Specialist
