While I am no expert on this subject, I read an article that said that the earlier CDs were recorded "soft", and did not make use of the full dynamic range that CD offered. Later,I think in the '90s, they discovered that they could get better dynamic range, and better sound, by recording them "hot". So, if you check when these CDs that you are talking about were made, you may find a correlation.
CD volume levels
I'm a bit confused by various recording levels I've found on CD's. While most fall in a narrow range of mastering/pressing levels, every so often, I'll run across a CD that was manufactured with a really hot (loud) level, while others are rather anemic (soft). I'm not talking about compression or limiting on the master tape, just the absolute mastering level on the CD. While I understand the physical limitations of cutting vinyl (a combination of science, art, with a little voodoo throw in for good measure), why would there be such a variation in the digital domain? Are there trade-offs with different levels when pressing CD's, just as on the analog vinyl?