Converting from event back to MIDI results in severe, unpredictable tempo distortion

[iLykTurtlz]

I've spent some time with the docs looking for a workaround, but no luck yet. I need to be able to convert back to MIDI from the event representation, but it doesn't seem like the conversion operations are symmetric. Here's my code:

`
data = muspy.Music21Dataset() #current music21 interface incompatible with muspy
data.composer = 'bach'
data.filenames = music21.corpus.getComposer(data.composer, fileExtensions=data._extensions)
dataset = data.convert(root="./bach_data/")

#test that the first file is not corrupted
dataset[0].write_midi("testing0.mid") #ok

#from MIDI to event representation
pytorch_bach = dataset.to_pytorch_dataset(representation='event')

#from event representation to MIDI
result = muspy.from_representation(pytorch_bach[0], "event")
result.write("bach0.mid") #not ok
`

Any suggestions would be greatly appreciated!