This article provides information about the validity period after the replacement of the VMCA certificate with a self-signed certificate.
When you replace the VMCA certificate with a self-signed certificate with vCert script, its validity period is set as follows:
Not Before: < 3 days before the date the replacement was done >
Not After: < 3650 days from the new "Not Before" date >
For steps to replace the certificates, see vCert - Scripted vCenter expired certificate replacement