I encountered this issue too.  It seems to be related to passing too large of an input to the CUDNN RNN layer (in my case, a GRU).  I found that reducing the batch size made the problem go away (and the original batch size would have been way too big for me not to run out of memory anyway since even with a smaller batch size that didn’t cause the error I still ran out of memory and had to reduce further).  Also, for me it was not an intermittent problem but happened every time.