I had the problem with three identical tracks on Pixar Blu-Rays in the past. With "The Incredibles" there were three identical length tracks. As it turns out, there is a French, English and Spanish version of the same movie, and the only difference is the opening and ending credits (basically the title sequences). I have the French or Spanish track currently, as the English track refused to rip properly. It changes nothing, other than possibly the default subtitles as well. IIRC, the first of the three is the English version, then French, then Spanish, although this could be different on other discs.