Flamewave doesn't always work.  It takes the time to cast, but at least twice (in the same battle granted) it did the visual effect, but no damage occurred.

There is also a bugged quest that I have encountered several times.  It is rated strong, and while it occurs naturally it seems to occur every time I use the quest map item.  The basic idea is that the people of an inn have been kidnapped by wildings.  When you catch up to them, you have three options: fight, pay ransom or ignore.  When I fight and win it says that I successfully freed the captives, and they have become a pioneer in my service, but no such unit appears, independentally of whether I had room in my army or not.