Question regarding PSK

[FBFAN]

This is a question regarding High School football in California

Team 1 has the ball, 4th and 8. They decide to punt. During the punt, team 2 has 12 men on the field. Team 2 fields the punt and is tackled for no gain.

The flag was thrown and Team 2 was penalized from the spot where they were tackled and kept the ball.

The ref said Team 2 keeps the ball even with 12 men on the field, due to the Post Scrimmage Kick rule.

Is this correct?

Shouldn't team 1 get the ball back?

What is the PSK rule?

Thanks in advance.