If these are non-expander backplanes, I'd suspect something either in the SAS second path connector or the SAS pin 3 problem. I can't find high-resolution pictures of the Funtin to see what it is doing with either of those.
Appreciate the response!
I haven't focused on the backplanes or other hardware much because the issue occurs on two completely different backplanes/motherboards/chassis, and only with the PM963's. Intel 750's, P3700's, & Samsung PM951's seem to function normally. Early on (before I foolishly flashed all 12 drives with what was supposed to be the latest PM963 firmware), two of the twelve PM963's had the original firmware loaded and did not exhibit the firmware crash on reset..