Wait listed at cal poly

My son got accepted out of the waitlist today. He checked his portal last night around 11pm PST,
and there was no update. He received an acceptance e-mail today at 4:50pm. So,his portal was
updated between 11pm yesterday and 4:50pm today.

Economics major, In state
ACT 29(Math 35)
SAT Math 2 760
GPA 4.1

He is also waitlisted by UCI,UCSB,and UCD.