i'd probably blame the compiler. It's a weird mess of DEC objects being glued together to run on NT (Like the MIPS/PPC ones too). And if you wanted to make anything that for sure ran on all CPU type's you'd build /Od. Doing /O2 or /Ox was a recipe to run nowhere.
The real shame is that 64bit beta compiler does such a substantially better job on the Alpha, but like everything else once everything started to gel, it suddenly imploded.