Cal. Insurance Code § 11624.09

Upon a determination by the plan that a certificate of eligibility is defective due to an omission or mistake which is immaterial to determining the eligibility of the applicant for coverage, the plan shall immediately provide written notice of the defect or defects to the insured and to the agent or broker of record. The notice shall inform the applicant that he or she has 10 days from the postmark date of the notice to correct the defect and postmark the correction or missing information for return to the plan. In the event that the defect is not corrected within that 10-day time period, the policy is void from inception. Providing a photocopy of the application or certificate denoting the specific defect or defects shall be adequate to comply with the requirement to specify the defects in the certificate. For purposes of this section, failure to provide a required telephone number, time of day, producer number, producer signature, date or information that is omitted but can be determined by questions answered or information provided in other sections of the application or documents submitted as part of the application, shall be considered an omission or mistake immaterial to determining the eligibility of the applicant for the plan coverage. A certificate of eligibility that is submitted to the plan as to which the applicant did not demonstrate a good faith effort in completing or where the applicant has made a willful misrepresentation shall not be subject to this section. In the event that the defect is material to determining the eligibility of the applicant for coverage, the policy is void from inception.