how are universities sent results by UCAS?

just curious but does UCAS update our application in the track education part and unis view there or does UCAS send the list to the university directly? i have AS chem listed alongside A2 for some reason and I'm worried they'll make a mistake lol

UCAS receives it from exam boards via Electronic Data Interchange. It then forwards it to the universities using xml-link. If this doesn't make sense to you, just think of it like this.

It shouldn't get mixed up.
Track stops updating a few days before results day so that admissions staff can process it. It start to update results day around 8am.

so would they see all my results in one document and log it that way as opposed to ucas automatically assigning grades to the subjects on the education part of track?

Ucas will use the information in your application to initially match results to your application.
If you have a qualification listed as pending that will not get a grade in August then your application might be flagged as “incomplete results” which may cause delays.
There’s a form on the ucas website to make changes to your pending results if they’re wrong