"Hey Cortana" Won't Stay One

[rchapman80]

So I have a Surface Pro (2017) that is running the latest fast ring. I have only just installed it to try out light mode (love it BTW). Since then the "Hey Cortana" always listening feature will not turn on. I flip the switch in settings and then it just changes right back as soon as I leave the page. I haven't found anything that says this is a preview bug so it could have happened before I put the fast ring on it.

I know that running the fast ring preview has it's bugs and I know that's the price I pay for using it. So if its the preview I'm not too concerned.

Is anyone aware of this issue? Any way to fix it?