Lightroom Mobile - Flash Won't turn on in DNG mode

I'm really confused and I'm hoping it's just me and not the app. When I take photos with .jpg the flash can be turned on and it stays on. When I switch to DNG mode the flash turns off and the flash button is not active. I can't even turn it on. Does anyone know how to fix this? It's very annoying as I can't take any DNG photos in low light locations.

I'm using iphone 6s and ios10.