I suppose it all has to do with how much creative work one label puts into it prior to another label re-issuing it. There are so many reissues happening lately and giving credit to all of the persons involved in locating the elements or preparing them for an album can be tricky. In the case of Studs Lonigan, I did save the music after Dub Taylor found it back in the 1980's and I did master it for a CD release, only to see the credit go elsewhere. But I survived. It happens. To balance things out, Jose Benitez turned around and accorded me producer credit on his own subsequent reissue - so it sometimes works the other way.
We couldn't have done our Master Of The World release a few years back if it hadn't been for Bruce Kimmel saving his elements from the old LP Varese LP days. In kind, we saved everything from Quigley Down Under, making the expansion for Prometheus possible. But we didn't do anything particularly creative, we just passed on to them what apparently were the only surviving masters. They did all of their own work after that. So when little creative work is being transferred from one label to another, seeing the credits follow everywhere in kind isn't really practical. I've seen Kimmel, Redman and Kendall all accord credits to fellow labels in many instances so these courtesies can and do happen. It's nice when it does happen but it's just too impractical to expect on a regular basis. Seeing it done once in awhile is pleasure enough.
I've noticed most major labels doing reissues - such as with RCA's many Mancini albums throughout the years and Mercury & Verve's many jazz and soundtrack projects - all typically accord original album producers credit. But "us" boutique soundtrack labels are a much smaller breed.
I think the only time I really felt "cheated" was when, after several mediocre versions of Flesh + Blood came out on different labels with different producers, we located for the first time the 2" masters, where upon we undertook great time and expense to completely remix and restore the entire score, including extra material... only to see our album used as the source for another label's reissue - alas - with someone else taking credit for all of my creative work. Kind of a no-no in my book. But that's because genuine creative work was involved, including numerous artistic decisions, musical choices with regards to instrument positioning, solo colors, dynamics, panning of the orchestra and whatnot. I myself would feel bad slapping my name on artistic work done by someone else. Obviously, not everyone in the music industry feels this way.
I understand the Varese release of Lock Up uses our album - and my creative work - as their source. I certainly don't yet know this to be true so commenting on it is probably meaningless. But, sadly, the label has traditionally been guarded about according credit to their fellow labels, or sometimes even acknowledging that there are, in fact, other labels producing film music. That probably isn't going to change, but miracles do happen. Our finding all of Conan is proof enough of that.

--Doug