Old thread I see but just came here to say I was just having exactly the same problem as OP, same errors - btrfs drive just would not get recognized and I tried all the steps in this thread. I thought it was done and dusted. Loaded up "sudo fdisk /dev/sdf" ready to format the drive, which threw up the following:
I hit "w" and wrote the change, then tried lsblk -f and the drive was assigned the correct label and UUID and became mountable.