Copying my comment from the edit note discussion here, because it deserves repeating:
I fully agree with you that copying matrix codes from associated Discogs links is too unreliable to base editing decisions on. Ideally, that information is documented in the uploaded cover art and the annotation field. This why it is super useful to list the DiscID together with the matrix information in the annotation, like is done in this release:
In addition, it is good practice to support that information with scans from the matrix/runout information, as I have done for example here.
@UltimateRiff wrote a helpful guide for assisting people in understanding and documenting this information.
spread the word 