Originally Posted by ncpl
DSP speakers are only able to render not decode
So when you set to expect external decoder the speaker cannot decode. It therefore processes the signal as FLAC.
Well that explains it.
The good news is there's still a way to play MQA.

Main: Marantz Cinema 50, Meridian 271, DSP7200.2, DSP5200HC, DSP5000 rears, Meridian 210.
PC/Headphones: Mytek Liberty II, Sansui CA-F1, Sansui B-2301, Sennheiser HD800, Kef R3