I’m not sure if this is related, but we’re also experiencing an issue with BuddyPress.

When attempting to delete a term in wp-admin, we get a similar error message. We’ve discovered that the issue disappears when BuddyPress is deactivated.

This started occurring after we accumulated a large number of terms in a custom taxonomy called “Series”, which is used by the PublishPress Series plugin. At the moment, we have 440+ terms in that taxonomy, and the number is steadily increasing.

I haven’t yet tested reporting an item with Moderation Tools while BuddyPress is deactivated to see if there is a connection.