Cast actor credits wrongly listed as 'self'

Hi there. For some reason in the past week some of the cast credits on the show Armchair Detectives https://www.imdb.com/title/tt7645634/ have changed from 'actor' credits, to 'self' credits. They appear on the main https://www.imdb.com/title/tt7645634/ page as their cast 'actor' credit with their character name, but when you click on their individual page their credits list in the 'self' category. Any idea why this has just happened in the past week or so, and if there is a way to change back the credits on the individual actor's pages? Thanks! Mark