I’ve looked at the database and discovered that all the corrupted categories have a term_id of 0.This is the case under terms, term_taxonomies and term_relationships. Changing the term id of one of the corrupted terms causes them to no longer show on the list of categories in wordpress’s categories section.
I do not know how the database became corrupted, this was a pre-existing site I took over management of for a client.The first corrupted categories are related to woocommerce, so it looks like that is when the issue began.
Unfortunately because it looks like the problem began some time ago, a database restore will not solve the issue.
It looks like a rebuilding of the affected database sections will need to be done to resolve it.
