I just had a look at the recipe and it seems like the error occurs when the existing annotations from the dataset are added to the pattern matcher model. Is it possible that your set maintenance_reports_annotations includes other types of annotations that are not NER annotations? Or something without a span? And does the error go away if you use an empty dataset? (You can also set the environment variable PRODIGY_LOGGING=basic to see what’s going on behind the scenes.)
Btw, It’s probably unideal that ner.match updates the matcher and resumes by default – it’s a nice feature, but we should probably add it behind a flag.