Spacy v2.0.1 custom NER: How to improve training of existing model
The model depends entirely on the training data: if you train with some data which has only PrdName as label, the model knows only this label and can predict only this label. You need to provide as much training data as possible, containing all the possible labels.

For the record, NER are usually trained with thousands of sentences in order to account for the diversity of the cases where a NE can appear.