vSphere 5.1 Permissions Not Propagating

When I add permissions at the data center level with the propagate option, I see the account in the permissions list on the individual servers but the privileges aren't taking effect. The privileges only work when I add the account explicitly to the esxi server.

For example:

• My Datacenter (permissions: MyAccount:Administrator w/ Propagate)
  • My Cluster
    • My Server 1 (permissions: MyAccount:Administrator (inherited))

The privileges for administrator are not in effect for user MyAccount on My Server 1. However the privileges do take effect when the account is explicitly put on My Server 1 in this configuration:

• My Datacenter
  • My Cluster
    • My Server 1 (permissions: MyAccount:Administrator (explicit))

Any idea why privileges aren't taking effect for the inherited permission?