Thanks to @whofferbert post here: MODEP no longer running following rpi-update we have figured out the hotspot issue. Turns out the script for starting the hotspot was exiting early due to there being no Pisound board attached, in order to be able to flash its LEDs indicating whether the hotspot is getting enabled or disabled. Needless to say it was not the intended behavior. 
I have just pushed out a fix to pisound-btn package (version 1.09-2), which contains the scripts to start and stop the hotspot.
Try doing:
sudo apt update
sudo apt install pisound-btn
Then run patchbox and (re-)enable the wifi hotspot, it should work this time.