Yeah that happens because horizon saves the state of vcenter in the associated ldap database on the connection server, the same thing if you rename anything else. Horizon, at least it used to, doesn't actively check for updates every few minutes. It expects  things to be the same, I'm assuming the "fix", is to handle that inconsistency better, but if we don't make only vcenter side changes that aren't 100% necessary this won't happen regardless.