TVDB has a rare issue where their server updates may contain old cached meta.  This can lead to broken meta for a period of 24-48hrs, from what I've seen, until the cached meta is brought current. Oddly some api keys the cached meta is more current than another api key.  This option allows you to switch api keys in hopes the cached meta for that key is more current. This option is a temporary solution for people who can not wait for the update to complete across TVDB servers.