I have just bought an adapter and I am going to try my own test, it could have just been the adapter he had, lets hope that is the case. I think he said he thought the issue was to do with the lanes it was using but I don't think that's how it works when interfacing via USB.
usb 3.1 controllers picks up pcie lanes iirc.
i would definitely love to know of a known to work with acorns usb to m2 adapter. as i have the feeling my current two mining mobos may wind up with some acorns on the wrong side of the PCH as the 1080tis i want to pair them up with. of course the usb may be on the wrong side too but i think it depends on which usb ports i use on the mobo.. wont know till the Soon
(tm) to be released gpu boost miner arrives.
I might be fucked up on cold medicine too but I'm pretty sure you're talking about the acorn accelerating GPUs via USB? My first task is to get it solo mining via USB since it won't need 4 pci lanes to take full advantage of it.