I believe the term used in the article is “steadfast non-standard belief”. Please refer back to the published version of the article.

“Persistent False Belief” does not appear to be one of the categories listed in the findings. Is that an alternative name for one or more of the categories?

I read the report and it is very preliminary. Most importantly it missed perhaps the most germane possible cause of the spreading of misinformation, the inability of a significant portion of the population to engage in Rational thought. Without that ability and practice, a significant portion of the population simply cannot determine if something is true or false. Instead they make decisions based on associations with others and simply repeat what they read or hear without any critical analysis. This per Daniel Kahneman and Amos Tversky. I find the continued assumption that humans are rational actors in analyses such as this truly miss one of the simplest explanations and blindly ignores research that truly could illuminate the phenomenon under study.