"Aaron Carter's Coming to Town" (https://lizziemcguire.fandom.com/wiki/Aaron_Carter%27s_Coming_to_Town) had production code 118, but it was originally aired as the 7th episode of Season 1. Does anyone know why?

This consequently, caused a continuity error where Lanny (https://disney.fandom.com/wiki/Lanny_Onasis) is mentioned, though he doesn’t first appear or get introduced until the 13th episode. That episode in itself was actually filmed before the Aaron Carter episode but aired much after.