When I put 2 or 3 batteries in the charging hub, only 1 battery charges. The battery that charges is random each time, it’s usually the one in the middle slot.

I can charge them each individually but when charging them 2 or 3 at a time, only ONE charges.

So the issue is that the charging hub is not charging all the DJI Mavic Air 2 batteries at once. I am forced to charge them individually.

I have successfully flown the Air 2 multiple times with each battery and have updated all the firmware. I got the drone a about 2 weeks ago.

I saw this thread: https://forum.dji.com/thread-214934-1-1.html
But that did not resolve my issues.

And yes, when I first got the drone, I charged each battery individually without the charging hub to get them out of sleep mode.

So does anyone know why my Mavic Air 2 charging hub only charges 1 battery at a time?

from dji.com:

Mavic Air 2 Battery Charging Hub
USD $59
Charge 3 batteries in sequence
Compact and portable

When connected to a Mavic Air 2 charger or car charger, the Mavic Air 2 Battery Charging Hub can be expanded to charge three additional batteries.
It is designed for use with the Mavic Air 2 Intelligent Flight Battery.
The battery charging hub enhances efficiency by charging batteries in sequence according to their remaining power level, with more fully-charged batteries receiving power first.

Because that's the way it's supposed to work.  And assuming it's like the similar charger for the Mini (what I fly), it charges whichever battery has the most charge to start with.  The idea is to get you a fully charged battery in the least amount of time - so you can go flying sooner.

Please read DJI instructions regarding battery hubs.

Hello there JoeGatto. Thank you for reaching out and for the information you have shared. The DJI Mavic Air 2 Battery Charging Hub charges 3 intelligent flight batteries in sequence and the said battery charging hub enhances efficiency by charging batteries in sequence according to their remaining power level, with more fully-charged batteries receiving power first. Thank you.

I guess you did not read the manual mate

Indeed, the charging hub is a sequential charging hub. Meaning when you put three batteries on the charging hub, it will scan the batteries to see which one has the MOST charge and then charge it first there by getting you back in the air quicker. Then it will charge the next battery with the most charge and so on until all batteries are charge. There by a sequential charger.

Way late to THIS party, but I just purchased an Air 2S, and attempted to charge all three batteries with the hub.  It worked great except for the middle battery; it was apparently not brought out of hibernation by the charger/hub.  I removed the other two batteries (which were successfully woken up and fully charged), cycled the charger power, and Battery 2 is now charging as I write this.  It's interesting that nobody who responded to the OP (who was having problem with Mavic Air hub, likely same hub as the Air 2S) actually took the time to read his post.  Anybody else have this issue (with the hub, and not the responders)?