Repeatable crash w/bluetooth error

[bmn001]

Pi Model or other hardware: 3 model B
Power Supply used: 2.5A
RetroPie Version Used 4.1.12
Built From: Started with a 4.1.10 SD image, then used setup script to upgrade to 4.1.12
USB Devices connected: none
Controller used: 8Bitdo NES30 Pro, Bluetooth
Error messages received:

/home/pi/RetroPie-Setup/tmp/build/emulationstation/es-core/src/InputManager.cpp:67 void InputManager::addJoystickByDeviceIndex(int): Assertion 'id >= 0 && id < SDL_NumJoysticks()' failed."

Log found in /dev/shm/runcommand.log (if relevant): n/a
Guide used: none
File: n/a
Emulator: All
Attachment of config files: n/a
How to replicate the problem:

If I exit any emulator, then power off my bluetooth controller right away - before EmulationStation has a chance to fully reload - I'm dumped to the command line with the following error:

emulationstation: /home/pi/RetroPie-Setup/tmp/build/emulationstation/es-core/src/InputManager.cpp:67 void InputManager::addJoystickByDeviceIndex(int): Assertion 'id >= 0 && id < SDL_NumJoysticks()' failed.

At this point my Pi no longer responds to keyboard input and I then have to powercycle to get things back to normal.

I tend to run into this a lot, because when you're done with a gaming session that's what you'd do - exit the emulator and turn off the controller.