Blackfire replaces Starfire by the end of episode 2 and the others make sure she copies her completely so no one will notice.
This apparently worked well in real life. Although she drops character every other episode, the Youtube comments always say "Oh yeah, I forgot she was Blackfire!"
Schedule Slip: Episode Seven comes eight months after Six, with an Apology Vid about in the middle of the break. And then, Episode 8 came out a year after episode 7. Episode 9 finally came out, almost a year later. Episode 10 came out 2 months later. 9 months later was Episode 11 and 9 months after that finally came Episode 12 (which lampshaded how long it took to get there), which ended the season (they skipped Mad Mod).