I don't think Blu-rays are even suspectible to "rot" in the same way as all layers are internal, there is no external joining of separate plates as in DVD (and most of the "rot"-afflicted titles, to the best of my knowledge, went a step beyond that and were DVD-18s with two dual-layered DVD plates joined as a flipper disc). If any BDs were to experience the same form of "rot," I'd expect it to be Universal's BD/DVD combos.
There was a problematic batch of The Prestige (and also apparently the original release of Stranger Than Fiction) where a contaminant was found in the material used for the clear-coat protective layer. This manifested as a series of discolored spots on the bottom of the disc, and resulted in the disc not being readable. This information comes via paidgeek, a Sony employee who apparently tracked down this particular issue. Assuming this is all true, that would just fall into "bad batch" territory, and not be indicative of an inherent flaw in the Blu-ray disc manufacturing process.
For the past year or so, I have seen isolated posts on various forums discussing Blu-ray discs that at one time worked, but now no longer do. The overwhelming majority of them have been early Lionsgate releases (American Psycho, Basic Instinct, and Lord of War spring to mind). I don't mean to jump to conclusions as certainly nothing is verified and other possibilities exist, but the simplest explanation here is just that early batches of Lionsgate discs also had a manufacturing error of some kind, although it would seem to be a different one as errors are occurring over a more drawn-out timescale. I feel if it was a general Blu-ray manufacturing problem, it would occur not just over a wider range of discs, but in larger numbers of discs as well. But I suppose time will tell.
I'm at a tech conference at the moment, but when I return home I will try to find and test my various early Lionsgate BD releases. I purchased mine in late 2007 so they may not be from the earliest manufacturing batches, but I'll still see what I can find out from them.