Well, I am sorry for the unpleasant experience.
Restarting hostd (the management agent) is not such a dangerous thing as it might seem from my post, especially when the host is a standalone one, i.e. there is no vMotion, DRS, etc.
You may want to have a look at these articles for more details:
VMware KB: Restarting the Management agents on an ESXi or ESX host
Another good news is we have found the reason for this bug, it will be fixed in the next release.
Regards
Plamen