Translation example generates the same input
I trained the [translation](https://github.com/huggingface/transformers/tree/master/examples/pytorch/translation ) example, using a custom json file with the format specefied in README. 

It has a bug, I don't know where, but strangely it just generated the same input. For example if you set `--do_predict`, the `generated_predictions.txt` is some of (or in language or format) of inputs. 
Hey @puraminy,

Could you provide a reproducible code snippet? Otherwise, it's very difficult to reproduce the error you got.<|||||>@patrickvonplaten 

Here is my code on github

https://github.com/puraminy/mt5-comet

you should be able to run `run_trans` in the root folder. You can see my settings there. I also changed `run_translation` a bit to adopt it with my local data. 

The data were also provided there. For test I decreased the number of train and test data in input parameters. I didn't check it recently, but I guess it's the last one with the error I specified above. 
There is another seq2seq task, which follows run_translation, named run_comet. That task is for English 2 English. It also generates the input than target. 
However, for now you can first try `run_trans` and for example check the generated texts by `do_predict`
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