It was not an auto admit but UCSB opted not to have the PIQ’s read by a 2nd reader since the scores given were high enough for this applicant.
The auto admit was mentioned by the OP which is a misnomer. They were a strong candidate so a 2nd reading was not needed.
The UC’s consider 13 areas of review criteria and will decide if parts of the application require only 1 reader or 2nd or even a 3rd review.
Here is the discussion: What Happens after UC Admissions Readers Grade Your Application?