Missing X-Men Episode?!?!?

I purchased X-Men the Animated Series volumes 3 and 4 today, but prior to my purchase, I was aware of Buena Vista placing the episodes out of order on the actual DVD's.....when I got the DVD's home I looked over the correct way to view the series, and then looked for each episode....while doing this I realized that the episode "No Mutant Is an Island" is not included on the DVD.....has anyone else had this problem? Has Buena Vista mentioned anything about it?