Dan here is what happened,
The mistake was a misinterpretation of the rules regarding "judges' preference." In UIL there is a rule that states if a band receives a ranking of 1,2,or 3 from at least 2 music judges and 1 marching judge, they will advance to the SMBC regardless of their final placement. Del Valle came in 5th overall but had a ranking of 2 and 4 in music, and a 3 in marching. ( Warning-- I have not seen the actual recaps-- this is hearsay, but from reliable sources!) The contest administrator apparently thought that since the AREA was advancing 4 bands to state, the ranking of "4" in music would count towards this policy. That was the mistake-- it should not have counted, the rules clearly state " 3 or higher". However, during the challenge time, where mistakes can be challenged and rectified before becoming official, no one questioned this. And so the results became "official" and were announced. About an hour later someone, apparently from the Austin office of UIL, clarified the rule, and Del Valle was informed they were not advancing.
But an update from Uil, they had advanced Del Valle, which the band drew the 11th spot for preliminary at SMBC