I have DECnet Phase V set up on my x86 community package running VMS 9.2-2, mainly because it did not come with Phase IV. That pushed me into learning Phase V "stuff" after 30 years of managing to avoid it.
I do find that it takes a few minutes after booting for it to recognise that Phase IV nodes exist on the LAN, but that it works at a sensible speed after that.
I only have the one Phase V system, but several Phase IV systems, so perhaps it is expecting to find other phase V nodes "out there" and getting confused when there are none.
Cheers
Peter Allan