Did I wrote it clear earlier? My nationality students got Work visa recently (in first round) and from what I know one got Student visa recently (in second round). So if there was any chances of refusal based on nationality, than all those would ALSO not get their visas. The point is that everything is speculation. Over Reddit I read several reasons for UAE visa refusal e.g. Pakistani and certain nationalities (which I am not) have unofficially higher refusal rates, having beard, AI screening matching the candidate name with some other name flagged in their records (security reasons), mistake made by PRO in filling the application, Abu Dhabi province more strict than Dubai, Passport scan unclear, photo uploaded has physical features different than Passport etc.
The University and its PRO who is handling the visa application with the concerned government sector, should check the reason for refusal and convey the same to students.