I have had a similar experience with dumping a PC disc on the PX-760A in the past. Unfortunately, I can't recall the game, but I had a disc that would report no C2 errors when dumped on the 760A, but it had 2-3 ECC/EDC errors when checking sectors after the rip was done. I later used a PX-716A to dump the same disc, and it was free of ECC/EDC errors (and, IIRC, it reported C2 errors in the spot where the ECC/EDC errors were present in the 760 dump, but DIC re-read successfully).
I think the C2 reporting on the PX-760A must have some limitations, and I wonder if there are certain data patterns that are problematic. I think it would be nice if DIC had an option to re-read in cases where there's no evidence the sector is protected (e.g., not part of a protected file and no 312 bit C2 errors or similar) but the ECC/EDC data doesn't match, because there are definitely instances where the 760 (and maybe other models of Plextor drives) will claim no C2 errors but still have errors. And, it's not just a "rip it again and it'll work" situation, either. I ripped that disc probably 4-5 times with the 760A, and it never had C2 errors, but it always had ECC/EDC errors. In contrast, the 716A reported C2 errors in the same spot (IIRC) and successfully re-read.
I guess this is kind of in-line with opinions on the 716 vs 760. Lots of people from back when the 760 came out claimed the 716 was a much better drive than the 760. However, it seems like the 716 drives have reliability problems. The 716 I used to dump the disc that the 760 failed to dump only works when it's feeling up to it. The rest of the time, it just goes into some kinda laser focusing frenzy and rattles the laser lens up and down like it's dancing. It happened to work fine to dump that disc, though.