my experiences with the bluetooth dongle and the edge have been temperamental at best, but I think I know why;
From my observations, the 5v circuit that powers the bluetooth dongle isn't strong enough to provide a consistant power feed so it works correctly/reliably. This is made considerably worse if you have a PAS connected (Throttle, PAS, and BT dongle all operate on this circuit) as anything else connected to the 5v output causes voltage sag and makes the BT dongle misbehave.
I found this out because, my first controllers 5v circuit crapped out after a weeks use and, as my throttle wasn't getting the 5v it needed, it only output around 30% throttle/6mph ish when twisted to full - basically, the 5v circuit was dying. At first I thought my bike had entered some sort of "limp home" mode - nope, the throttle just wasn't getting the power it needed to actually operate.
Needless to say the BT Dongle also didn't get the power it needed to operate effectively.
Unfortunately the only solution was a replacement controller.
So, I got a replacement controller and investigated further. I noticed a similar behavior on the new unit; throttle, PAS, bluetooth dongle all connected, my speed dropped slightly (say by about 2mph ish - again because throttle isn't getting the 5v required to work 100%) and bluetooth became less reliable if I had PAS fitted. This is with a brand new, 2020 version controller for the EDGE (Previous was a 2016 model, according to sticker. The new one seemed to have a second 80v capacitor attached to it).
TL;DR, the Bluetooth dongle only works reliably if you disconnect your throttle and/or PAS, do your programming, then remove it. basically, reducing the load on the 5v circuit makes it work correctly. This circuit is just not adequate enough to power that + PAS + Throttle for the bike to function properly which is quite a disappointment considering the cost these motors are.
Really, GM aught to fix this major issue as it also robs us of usable power via the throttle.