In the very first version of the game, the vampires had these green icons; I assume this was fixed in the very first patch.
Added 5 minutes later
My Heroes V came on four discs; it took a long time to install. There was no "recruit" difficulty setting; the vampires had green icons, and the music in the cities didn't reset when I left them. There was also a funny detail: random cities on maps have default names and biographies, but after launching the game, they change. Previously, they didn't change; I saw a Sylvan faction with the name of a Necropolis.
I didn't know about the green icons... well, at least I don't remember that...
and griffons also limped like zombies, Rakshasa had 8 arms on each side, and Titans spat dragon fire instead of lightning? ))))))