DJI just released a firmware update today May 16th, 2020 addressing the battery issues they were having with the Mavic Air 2. Many experienced their batteries not working myself included due to them not breaking them out of hibernation mode apparently the correct way. This hopefully resolved anyone having anymore battery issues in the future. I would still charge individually first and then update the firmware of each battery before using your hub in your Fly More Combo. Hope this helps and happy flying! Aloha
Go to 1:52 if you want to go straight to update info.
FULL length 4K 60 fps upload of some Chicago sample footage here. https://www.youtube.com/watch?v=addffjfekig&feature=youtu.be