Any ideas what is causing this issue? This keeps coming up whenever I start the DJI go 4 app and connect the drone.

Have you done the FW on your batteries! They need updating as well.

Did you run the update?

It looks like. Battery FW update as John has pointed to, when doing a FW update if battery update is included the battery in the craft will be updated with the firmware, but all other batteries need to be inserted and updated.

Hi, sorry for the inconvenience. May we know how many batteries do you have? Please make sure that the firmware of the aircraft and RC are up to date as well. Please let us know for further help. Thank you for the support.

You should always slide and update when you see that message. It'll update the firmware on the currently installed battery.

I get the same message, so I always update the software.  I have 3 batteries.