Some years ago, I renewed my license, but the CA DMV made a change to a new computer system at about that time and I got lost in the data transfer. When the new license didn't come in the mail, I went to the DMV where I was told to wait another 90 days and got an extension stamp on the back of the old license.
A few weeks later, my license was inspected by officer Kilby in Hollywood and was told that the DMV does not stamp the back of the license to extend the expiration date and got a ticket.
I wet to court and was told to come back and show a valid license and the ticket would be dismissed. So, I went to the DMV to see if I could get a copy. No, they can't issue a new copy until the ticket was cleared. No, the ticket can't be cleared without a valid license. No, the DMV and court can not get together and resolve their differences. It took 5 years to get it sorted.