Hey Eric,
So I just had a look at this and tracked it down to r.EarlyZPass being equal to 2 and not 3.
Virt has set this to 2 because all the docs about deferred decals advise to do so (Martin Mittring’s comment from April 2014, for instance), while in the meantime there was a commit in December 2014 that gave r.EarlyZPass=3 a new meaning, and it seems to me that this is what we actually need to have both D-buffers and foliage early Z working.
Bottom line, we’ve fixed this simply by setting it to 3, but you may want to update both the documentation and CVarEarlyZPass’s description in DeferredShadingRenderer.cpp to reflect this. 
Regards,
Leszek