I don't think technically there is such a thing as an MQA file. It's an MQA stream probably inside another container such as FLAC file.

Decoding an 'MQA FLAC file' will give an MQA stream, which is compatible with PCM stream. The issue is decoding the MQA stream - I suspect they are not, just treating it as PCM, upsampling and filtering to get for most, close to MQA quality.

Meridian owner since 1992
Prime & PSU, Focal Elear headphones, Roon (ROCK 8Gi5 NUC), Explorer 1 & 2, F80. 200/203, various Sonos (via Roon).