California Restaurant Docking My Pay For "register Mistakes" And I'm Not Sure If This Is Legal

Location: California

I work as a server in a small family owned restaurant. I get hourly pay plus tips, and we also run our own checks through the POS and handle cash. When I was hired, the owner told me they "expect accuracy" and that if the register is short, the person on that shift is responsible for it. I figured that meant we could get written up or maybe fired if it kept happening. I did not realize they literally meant coming out of our pay.

About two months ago I had a shift where the register was 23 dollars short at close. The owner checked the cameras and said he did not see any obvious theft, so "someone must have miscounted or comped wrong" and that it was on the servers to pay it back. On my next paycheck there was a line labeled "register adj" with -23.00 taken out. No one had me sign anything. Manager just said "this is how we do it here" when I asked.

Since then it has happened three more times. Once for 11 dollars, once for 9, and last week for 37 when the bartender voided a ticket and reentered it wrong. The owner decided to split that one between the three of us on shift so I lost about 12 dollars. It is not huge money each time but it adds up, and it feels really off that I can do my job correctly and still lose wages because someone else made a mistake. We do not get any kind of written report about what they claim was wrong, just a number and a shrug.

For what it is worth, we already tip out to the bussers and bartender, and we are making close to minimum wage after tip share on slow nights. Taking more out for "shortages" makes those shifts basically not worth it. I have never signed any separate agreement about being responsible for cash. My only paperwork was the standard new hire tax stuff and an at will employment acknowledgement.

My questions are: in California, is it legal for an employer to deduct money from your paycheck for register shortages like this when there is no proof you personally caused the loss. If it is not legal, how do I actually handle this without getting fired on the spot. Do I talk to the owner first, go straight to the Labor Commissioner, or just quietly start looking for a new job and report it after I leave.