Sea of Blood Spoiler alert!
In the avatar dungeon Area 1 for the Razorwing overlord, there are more Razorwings than are provided in the box.
Normally I would not be able to spawn them all, and I know that some dungeons from the Compendium have been Errataed.
However, this is an Avatar dungeon, unlike any other, I think it quite odd to put more monsters in the same area than there are in the box, and since this is a campaign and the last level I believe this to be somewhat a different case than just not being able to spawn.
Ex. Wedensday when we had our weekly campaign game, the team was in the Rumor dungeon "The White Drake", and they opened a door in the middle section before the razorwings had been killed, thus leaving me with 4 almost useless spawns. These were however in different areas, so I assume this is then also a different "ruling".