But now I'm curious! I know that that the vowels in Ryuukyu dialects are very different from standard Japanese. I checked those, and 'a' is the one vowel that is consistent within all of the Ryuukyu dialects. I took quick a look at some studies on vowels in Japanese dialects, but could not find anything about that sound(linguists write it as æ in IPA)existing in Japanese. I'll ask my linguistics professor to see if he knows anything else!

I assume that it's likely interference between English and Japanese. If you could find a link to the video, I might be able to listen for other clues. If it's a consistent pattern, then it could be a part of a dialect.