The bidirectional LSTM leak, which you linked, seemed to be happening to me for cudnn6 but not 5. My understanding was that it was not so much cudnn code that did it, but something in the build environment or so (not that the result is terribly different for us).
Unfortunately, something was up with my post in the NVidia forums back then (it never appeared there publicly even though I could see it when logged in) and have not revisited it.
I don’t know if similar things apply to CNNs.
Best regards
Thomas