On 1000 node RU I had 22.214.171.124-2557 installed with some 20 hosts down with heartbeat lost. Then I registered 126.96.36.199-2664 and when I proceeded to install, it would always get aborted with no logs in server or agents.
Turns out that whenever we install, we do so in stages containing 100 hosts each. If any of the host failed or timed out etc., the rest of the stages are aborted. So in this case the first stage had 1 host timeout, which resulted in that and other stages being aborted.
I cannot install a version without all hosts being alive. Workaround seems to be to delete lost hosts from Ambari.