There are provenance and mastering variables in files that are distributed by resellers and streaming services… A ‘Mono’ master source, most-likely will be digitally re-mastered as ‘Stereo’ and determined by the Audio Scan analysis algorithm, to reveal its true-nature of being a monophonic recording, because the L/R channel information being identical… It is important to dig-down into the provenance of the digital file to get the best insights…
This was discussed here…
