Matt,
Truly sorry I wasn't able to get to this sooner. Today is actually my first day on here contributing. In the future another way you can get these to disconnect is by connecting the ESXi host to another vCenter instance (if you have one). In the past when I've had issues with my host and can't disconnect it for whatever reason, I simply connect it to my Dev vCenter Server. I am then able to reconnect it to the original server.