Replacement card received from RMA submitted on Sept 7th.
Well, I couldn't find any real physical differences between the original and RMA card other than the different 330uF caps mentioned above. Same PCB revision code by the PCIe, same BIOS version for master and slave.
Old card serial sticker was "Made in China" and replacement is "Packaged in USA."
New card boosts lower (max of 1987, last one did 2025. Constant boost was 1949 before, now it's 1923 or 1911 or something like that. I'm not OCing at all) and considerably more coil whine than the previous card.
I really don't know what to think at this point. I would feel more comfortable if I knew what the actual problem was and I was 100% sure this replacement fixes the issue. I haven't had enough time to test with more games at this point, but I did run Heaven for a few hours and it seemed fine other than the coil whine.