I just found this "bug" in the 2021 firmware for xbee-wifi-s6b.
Here is the symptom:
First set up connection to an access point, let's call it A. Make sure the module is connected with ATAI response 0.
Next remove access point A (shut it off etc.). Now check ATAI response, it's going to be FF all the time. The module keeps looking for access point A.
Now make sure the following are all done without exiting the command mode:
0. Enter command mode
2. ATEE 2
3. ATID Access point B
4. ATPK PK for access point B
If you keep checking network association, you will keep getting FF, occasionally a 1. I used a serial port script to send ATAI periodically for a few minutes. Response is FF. Except, if I exit command mode, then enter it again, check ATAI, response is 0 on the first try, or a few tries later. If I do steps 1-4 then exit command mode. Reenter command mode, and keep doing ATAI, I will get 0 after one of a few tries.
So, why is the module unable to associate or report it is associated to an access point, if you don't exit and reenter command mode? A bug, possibly?