That's a beautiful but crippled analogy. VW and Skoda are almost rebadges of the same hardware. What you are running is an ancient Qualcomm SDK, with a crapload of their own stuff mixed in, and Gl.iNet has thrown LuCI on top of that. So compare it with taking your Skoda Superb to an authorised dealer, with a modern body (LuCI), but with a third party engine loosely based on their own (the SDK) in a configuration the manufacturer (OpenWrt) never delivered it. And the authorised dealer says: 'I'm not familiar with the stuff being pulled there'. That's closer to what you're experiencing.
I'm glad you found a pointer, but that thread you linked to seems to be from someone in the same SDK boat (running 15.05 in 2018...). So yes, it's a Gl.iNet problem, since by now OpenWrt has moved on and this has been fixed for four years.
Anyway - you can replace the hostapd script, it's just a shell script. Or patch yours. But make sure you're not removing other stuff in the process if you replace it. No need to recompile.