I also have the IOS equivalent, a third party wireless CarPlay puck connected to my 2017 Honda which doesn't have built-in wireless CarPlay.

I do believe that those things start with a brief bluetooth connection to the phone which then negotiates the handshake which hands off to the phone's wifi and drops the bluetooth connection. Not entirely certain about the way it works though.

If I understand it correctly, that AA Wireless device of yours is plugged into the car's USB port, correct? Mine needs the car's USB port. Basically it's a wireless puck which translates the wireless carplay communications into wired USB carplay communications.

The error message from the car thinks that your third party puck is still connected and it's still paired with it. Correct me if I'm wrong here... was your initial working connection this?

Car Stereo
|
Car Stereo's USB Android Auto Connection
|
AA Wireless Box
|
Your Phone's Wireless Android Auto Connection


And then something went wrong and it stopped working, so you tried to change it back to this:

Car Stereo
|
Car Stereo's USB Android Auto Connection (*)
|
Your Phone's Wired Android Auto Connection

And it still doesn't work because it's getting an error message saying that it thinks it's still joined to the AA Wireless Box. Am I reading the situation correctly?

If so, I think the error message is saying that the car stereo still thinks its USB AA connection is configured for that wireless box (*). See if you can find that connection and delete it.

The thing to remember is that this is all a completely separate thing from a bluetooth pairing. Simply telling the car to forget your bluetooth pairing isn't enough in this case, if I'm remembering correctly. You've got to dig in and find the AA pairing and delete that. I think.

You may have already tried this, so forgive me if I'm repeating something you already tried.