The Regents pick tentative dates for their regular meetings a year or so in advance. But the dates tend to shift for unknown reasons as the original selections grow nearer. For example, the upcoming September meetings at UCLA were originally set for Sept. 15-17. Then the last day was lopped off and the schedule became Sept. 15-16. Why? Not enough business to do? Your guess is as good as mine. But recently, a day was added back, but this time it is earlier. So now the schedule reads Sept. 14-16. Why the addition after the subtraction and the time shift? Who knows?
The schedule is at https://regents.universityofcalifornia.edu/meetings/. The Wayback Machine from the Internet Archive was used to track the changes: https://web.archive.org/.