I didnt know whether to make a support request for this bug, but I think this works.
Recently I initiated an RMA on my input cover, and I received a shipping confirmation email from Framework about my incoming package which included the tracking number and a handy link to FedEx where I could track it. 4 days passed, and the link (as well as manually inputting the number to FedEx) told me that the number did not exist, and so I figured it just hadnt left the warehouse yet. To my surprise the next day the package turned up on my doorstep, mailed through UPS.
TLDR; If your tracking number is invalid, try another PO company.