We need to add the following note to the agent-based install doc: 

In some situations, when you enable TPM disk encryption in the firmware for a bare-metal host and then boot it from an ISO that you generate with the Assisted Installer, the cluster deployment can get stuck. This can happen if there are left-over TPM encryption keys from a previous installation on the host. For more information, see BZ#2011634. If you experience this problem, contact Red Hat support.

Link to BZ:https://bugzilla.redhat.com/show_bug.cgi?id=2011634

    1.
    2.
    3.