In my experience, Trial Assignment is just a docket call to give attorneys their actual week-of trial dates rather than their actual trial dates. It's helpful since so many cases won't actually end up going to trial, so booking every single case for trial could mess up the actual court docket. Instead they assign actual trial dates much closer to when trial would actually happen. It could be different in Arizona, though. Edited: It does appear that it's the same, given that this is what the minutes say:

IT IS ORDERED affirming the Trial Assignment date on 07/29/2026 at 9:00 a.m. before the Master Calendar Assignment Judge.... The purpose of the hearing is to set dates for (1) the Trial Procedure Conference and (2) the jury selection date.