When starting a MQA in Roon it does like a dropout about 2 seconds in, and that I can't reproduce in foobar or Tidal desktop app. But those apps seems to have a delay, so maybe they wait for the DAC to be ready before playing (if that's possible), or just wait a couple of seconds.
But if you press pause and play again, or jump forward in the tune, the DAC plays PCM a few seconds before turning on MQA, same behavior in foobar, Tidal and Roon. This made me believe that Roon has lost the MQA, but its just seems to take a few seconds before the DAC switches to MQA.
So basically, what seem to be the core of the problem is that the DAC plays a few seconds of non-MQA before switching to MQA if released when starting, and in that transition you can get a drop-out effect (the tunes goes quiet for like a second). This does not happen during normal play or if you let one tune end and another begin, but pause/play, jump in a tune or a fresh start of a tune causes it (I would guess whenever the DAC is released and claimed).
Maybe not a big OMG problem, but if its possible to solve it would definitely improve MQA playback. I don't have any other MQA DACs to compare to, maybe they all behave like this.