After trying various simple models it turns out that PyTorch is doing exactly what it should and is consistent.  The problem is arising because the Glove word vectors for things it does not recognise such as ‘’ seem to change each time the program is run, which then means that the inputs to the new are changing.
I can avoid this by loading the entire vocabulary for all of the words I need in advance and then training using on the part of the data for which I have category information, then running the remaining data through the model.
I would appreciate any advice as to how others tackle this problem since it can’t be unique to me
Thanks
John