jack: ResourceExchausted Error when training BiDAF model on GPU with longer context data to SQuAD

Basically, when training on a 12GB Tesla K80 GPU on Google Cloud (you have to manually install tensorflow-gpu otherwise it defaults to CPU), I get a ResourceExhausted error seemingly during:

UserWarning: Converting sparse IndexedSlices to a dense Tensor of unknown shape. This may consume a large amount of memory.
  "Converting sparse IndexedSlices to a dense Tensor of unknown shape. "

For the regular SQuAD data, the GPU is only consuming 5GB of memory, but on the added data (with longer context lengths), it’s at max memory until exhaustion. The FastQA model trains fine on this data.