Legal Question in Employment Law in California

You are mistaken. If an hourly employee is called in to work the employer must pay for half the employee's normal shift with a minimum of 2 and a maximum of 4 hours, or the actual hours worked if they exceed the half shift. That does not apply to incidental brief telecommunications contact during non-working hours. If the employee normally works from home and is called to actually do work, as if an on-site worker had been called in to the employer's place of business, that would be different and would depend on whether the communication really constituted calling the employee to work or not. But for most employees who work at their employer's place of business, incidental telephone calls or txt messages do not require "call in" shift pay.