@lavaman Can't help on the battery issue, but I did have to send my XR back to FM from Oahu for the bluetooth issue and had the exact same issue with the hazardous labels. It took me four attempts to get FedEx to accept it, the first 3 times it came back to me the next day with little to no reason why. I had to speak directly to Jon in customer service at FM, who had to have his shipping department call the FedEx receivers in Oahu to figure out exactly what labels were needed and to confirm that they would actually accept it the fourth time, and they finally did. All of which took almost 2 weeks!
So, the issue was that even though FM sent me all the proper labels (which were the same labels they sent it to Hawaii with), FedEx receiving on the Oahu side wouldn't accept it without a call from FM to make sure they were aware of the situation. Seems like maybe FedEx has new people or forgot that they can actually accept the OW.