Adding vCenter fails, ESXi UUID conflict

I'm trying to add our vCenter to Unity, but it fails due to ESXi UUID conflict. I've tried to find a solution for this on the support site and on google, but haven't found any luck. I've checked the UUID on both ESXi hosts, and those are different. I'm getting the same error on both a real Unity and the VSA version.

Any Ideas on what the issue might be?