I remember writing to Mosaic when the Tina Brooks set was released and asking about the distortion on the Minor Move LP. Michael Cuscuna wrote back that there was distortion on Art Blakey's cymbal sound, nothing could be done about it and, for that reason, the session would never be issued on CD. I'm not sure if that's what you're referring to, but that's what I heard (and still hear) and that's the answer I got.
Well, a CD version was issued and, giving a quick listen to the Conn, it sounds as if Blakey's drums were mixed down enough so the distortion isn't as obvious as it was on the Mosaic LP.
Hope that this helps.