Promise from getUserMedia does not resolve (Firefox mobile android)

Question

For a while I'm struggling with a phenomena that on some android devices the promise of getUserMedia does not resolve (neither success nor error or catch). Even the prompt for the permission does show, but nothing after that happens.

It happens at having constrains that request an unsopported video resolution from the device. In my understanding that should result in ether a error with a respective message or another resolution for the stream. But nothing. I even have to kill the process of firefox for any similar request to work again.

If using the adapter-latest.js and testing the same code on Chrome it does work as expected and a stream with the next supported resolution is opened. That works on ALL devices.

Here is the constraint object, but I tested diffent version with min/max/ideal/exact parameter:

{
    audio: false,
    video: {
            facingMode: { ideal: "environment" },
            width:    { min: 800 }
   }
}

Tested with my current devices having Android 5.0.2 (working) and 7.0. (not working). Both use the same Firefox mobile version/build 55.0.2.

I tested it on Firefox mobile 46.0. and everything works fine.

So Any Ideas?