Hitachi Vantara appears to be in violation of the California WARN notification. The layoffs from April (and other rounds) have yet to be reported:
https://www.edd.ca.gov/jobs_and_training/layoff_services_warn.htm
Here are the penalties laid off employees in California are eligible for if there is a violation:
"A possible civil penalty of $500 a day for each day of violation. Employees may receive back pay to be paid at employee’s final rate or 3 year average rate of compensation, whichever is higher. In addition, employer is liable for cost of any medical expenses incurred by employees that would have been covered under an employee benefit plan. The employer is liable for period of violation up to 60 days or one-half the number of days the employee was employed whichever period is smaller. (California Labor Code Section 1403)"