We are starting to deal with this. Workers in CA are a PITA
One of the worst things about CA payroll is the requirement to pay terminated employees (whether voluntary or involuntary) on the date of their termination, for all wages due including accrued vacation, earned bonuses, etc., although CA is not the only state with that requirement.
Their overtime rules are funky too.
https://www.worklawyers.com/overtime-laws-california/