After having a team chat about it, it seems like the desire for key-coherency was just speculative, and we’re leaning towards adopting the python behavior - just forget TfNormPath() ever knew anything about drive letters.
It looks like TfRealPath() also does the same thing, currently, after reading/resolving the path through the OS, so we’ll stop doing the “correction” there, also, which I think should bring us into alignment with python.os in both instances.