Been flying and charging all day. Love it. But last flight something odd happened. The app showed the message "Controller not bound". I forced the take off and within a few seconds the message disappeared and stayed fine for the rest of the flight. Landed, powered off, and then powered on again. Same message. I let it sit for 3 minutes and the message stayed. I forced takeoff and the message disappeared. Anyone else see this happening? Should I worry? Previous flights this did not happen.

Glad it worked out but a safer move maybe to power down both the controller and aircraft and restart both and see if it goes away.

Do you have flyaway insurance? If so I have a recollection that binding the controller to either the drone or your DJI account, you'd need to check which, is a requirement for the insurance to be valid. If my memory is correct you will need to research that for yourself, I do not have the insurance so have not looked further into the matter.
"Binding" in this sense differs from the "linking" that is required to connect the drone and controller for the purposes of actually controlling the drone with the controller.

@Wiz33 tried that and same
@Sean-bumble-bee if that is the same as the refresh then yes, have that for 2 years.

Odd thing is went through another charge cycle and the message did not reappear. I am pretty sure the battery charging has nothing to do with the controller binding but it was odd. I went through another battery and charged up last night. I plan to fly again today and will see if the message stays gone or if it appears again. I searched and found people reporting this as a bug in the Mavic 2 series. I wonder if similar. And is related to the software. Perhaps a regression bug. No idea. I will keep an eye on it.

Flyaway may well be part of care-refresh but it is a separate thing and carries its own excess and conditions. If you do not KNOW of it or its conditions you should investigate, it's not an area where hindsight and or "after the horse has bolted" actions will stand you in good stead.

Still happens. Sometimes a flight is flawless and sometimes I get that binding issue message until I take off and hover a while or make some passes around my back yard.