That I don't know. I didn't start messing with certs and vCenter until 5.1, but according to a quick search it looks like it's something that started affecting upgrades to 5.0. (VMware KB: After upgrading to vSphere 5, you see the HA error: vSphere HA Cannot be configured on this host because …)
In the ESXi/SSL part of the article (Part 19) it is mentioned briefly. It's recommended to remove the host(s) from vCenter prior to updating the certs, and then reconnect them once done. I did a 5.5 host recently and forgot this step. The result was that the host got stuck in a perpetual election cycle.