My question involves employment and labor law for the state of: CA

So i have a timecard that i punch in and out of which is online. Every two weeks, we are requested to review and approve our timecards before we leave that friday afternoon to make sure there are no errors, as the timecards are submitted over the weekend(not really, they go monday before noon). This takes some time to do, and we are all off the clock as that is the only way to approve our time cards. We must clock out, then approve.

Is this legal? Technically, we are not getting paid since we clocked out. Shouldnt we be doing this on Monday mornings?