Why was the "Gambling Jag" episode from Season 6 aired out of order?

At the start of Season 6 (1989-90), Alyssa Milano sports a thick, medium brown, long past the shoulders hairstyle.

But beginning with the 8th episode of the season, "Supermom Burnout", Alyssa is sporting a hair style that's darker and cut to her shoulders. And yet, come the 12th episode of the season, "Gambling Jag", Alyssa's hair is once again the style that it was in the first seven episodes of the season.

To put things into proper perspective, "Supermom Burnout" was first broadcast on ABC on November 14, 1989 whereas "Gambling Jag" was first broadcast on December 12, 1989.