This issue occurs when the certificate refresh threshold is greater than the remaining expiry time on the certificates being created for the ESXi hosts.
When an ESXi host is added to a vCenter Server, it sends a certificate signing request for the host to the VMCA (provided you are using VMCA and not using custom certs for each ESXi host and pre-populating the /var/lib/rbd/ssl/host-id directory). The VMCA can only issue certificates which are valid up to the expiry date of either the machine certificate, or any intermediate certificate in the chain to your Root CA. The default value for the certificate refresh threshold is 240 days.