Unfortunately I do not have access to a computer for a while. Hopefully someone can try the regular release Tidal with .81. It may be that the regular release was OK all along.
The regular release was fine all along, I think.
With build 81:
Using WDM in exclusive mode in Tidal, with passthrough disabled; MC plays the Masters track and the MQA light lights up on my DAC. So, Tidal is decoding to 48 Khz/24 bit, and then MC is passing this on to the DAC, which is unfolding to 96 Khz+.
With passthrough enabled: MC is still receiving a 48 Khz/24 bit signal, but the DAC is still showing the final file at 96 KHz or 192 KHz depending on the track.
So at least the BSOD is fixed, and MC the WDM is able to pass on either a partly decoded MQA file, or an unmolested MQA file to my DAC to yield identical results in the DAC.
I'm happy.
The only issue is that there is about a 1 second distortion at the beginning of the first track played via WDM while the DAC gets a lock and understands it's an MQA file (I speculate).
EDIT (mistaken originally, as Tidal settings change didn't stick)
Also: the OP expects to see MC say that the input is 96KHz/24, and mine now does.
Further, if I play the same Masters tracks but using the Hifi (lossless) mode in Tidal, they play at the expected 44.1/16.