All the scenarios, which includes the campaigns, generally use all the same events, because it's all the same war with only time frame and area limitations.
Generally the theater campaigns simply have a trimmed down copy of the set of events used in the grand campaigns. But in trimming down, one event within the trimmed down set of events is probably spawning the units in NO.
If this were fixed, the units would simply not be spawned in, so in not being able to use the units, the outcome is the same.
Simply ignore that they are there and you'll be fine.