Not sure if the problem as ever solved, I have the feeling that yes. In a recent EL7 install, the first resinstallation of a machine that had a system disk with several partitions and LVM volumes in one of them, the first partition wiping/creation doesn't work: the test for the last partition (the partition which had the LVM volumes) never succeeds and the partition creation is retried indefinitely. Restarting the installation fixes the problem.