There is an issue of Responsive AA material flag working for only the right eye when doing stereo rendering for VR. This happens when using r.PostProcessAAQuality over 3. One could resort to FXAA to resolve that, but the resulting aliasing is too severe for my use.
Screenshot showing the problem:
Second issue is that bloom is not covering the whole right eye render (this is noticeable for the end user wearing the headset as well after the distortion pass). There is a portion missing from the left side.
Screenshot showing the problem (look near the area where the two eye renders meet):
Answerhub thread on the same issues: