The scale shouldn't count, as long as the examiner was made aware of the error at the time. If he wasn't, I would email the Area Rep right away, so that section can be corrected.
In an ideal world, mistakes wouldn't happen, but the amount of material/ grades/ instruments/ aural tests/ scales/ sight reading requirements the examiner has to be familiar with is mind-boggling. I have to check the syllabus very regularly, and I only teach woodwind. Well done to your DD for pointing out the sight reading thing.
BUT candidates can do the exam in any order they want. Trinity and ABRSM both usually provide sheets asking the candidate to write the pieces to be performed, in the order they want to play them. If they want to start with scales, sight reading or aural, they should tell the examiner at the start, and in that case they would enter the room without their accompanist. Some do, although starting with pieces is probably more common. There is also space to write on the sheet things like SEN, English as an Additional Language, which syllabus (old or new) is being used where there is an overlap, and which sight reading test is to be taken, if there is a choice. So as there was more than one possible type of sight reading, the teacher should have specified which one... as well as saying that DD wanted to start with her scales. Most of this sounds like an oversight on the part of the teacher, rather than the examiner. Next time, maybe you can get the sheet and fill it in yourself?
Anyway, I hope she gets a great result, and I hope some of this is helpful next time round.