Looking at the AssertionError above, it seems like the main issue here is that the data contains an invalid sequence (see the last few labels). So maybe something went wrong during the conversion?
'B-ORG', 'I-ORG', 'I-ORG', 'B-ORG', 'I-ORG', 'L-ORG'
^ start of new entity within open entity
Btw, quick update since it’s related to the topic: The upcoming version will also include a recipe ner.gold-to-spacy that lets you convert datasets to spaCy training data, both in “simple training style” and BILUO format. (There’ll also be a pos.gold-to-spacy recipe to convert part-of-speech tags annotated with the new pos.make-gold recipe.)