I had the same issue with a
Mavic 2 pro. I only had some success in fixing it.
Using Assistant 2, It only updated fully after I had first updated the controller.
Then updated the no flyzone database.
After that it did update but I was never sure if the update success message was just talking about the NoFlyzone or the drone firmware. and/or the battery firmware.
Eventually the same fault came up again after yet another firmware version update.
I tried everything with no success so I replaced the main core board. Then all was well.
That drone was fine until I crashed it into some flood water. RIP