Why does my RC keep saying I need a required update when it already has that update. Seems like a big waste of time to me. Always when getting ready to fly too. Really?

Turn on RC first, then open App, then start aircraft. See if that solves it. It's a glitch that I and others have as well. Starting in that order seems to take care of it.

That's the order I always use. I have the tablet on, turn the RC on, the tablet loads the app, turn the phantom on. Do I need to have the tablet turned off entirely?

I had this problem, that order of doing things does prevent it. However with the latest DJI go app update for IOS, it seems to have fixed the glitch. Since updating I no longer get the update message no matter what order I turn things on. I still turn them on in the proper order when flying however.

Please check the RC's firmware version. If it is the latest (for example, the firmware version of P3P/A's RC is 1.6.0 ), I'd suggest you to reinstall the app to the latest.