I just lost 3 days worth of work troubleshooting this one issue.
I've been deploying a RDSH deployment with remote desktop gateway.
What I noticed was that after the first time I installed everything the .rdp file being generated by rdweb was wrong.
I subsequently deleted the collection and remade it and it was fine after that.
Due to another problem I've been troubleshooting I ended up throwing the VM's into the garbage and restarting.
After reinstalling everything once again the published .rdp file was wrong.
More iterations allowed me to narrow down when I install the rd gateway service it would change the .rdp file as it should to add the remote gateway settings but would also modify other settings and make it incorrect.
I ended up basically fitting the description of insanity because i kept doing the same thing and expecting a different result.
So I moved over to another hyper-v host and redid everything. And everything came out as I expected.
I am seriously boggled at what has been happening. Is the hardware broken? Is Hyper-V broken? Is the Windows VM's broken?