Some adventures that you can buy belong to "The Evil Queen Campaign" (The Fisherman..., Hansel and Gretel, Pied Piper..., Red Riding Hood).
As I read the description of the event, the ventures that do reward the extra xp and loot, are not those that are on sale in the merchant because those are considered as seasonal event ventures, but the follow-ups on those ie Snow White, Unknown Regions, Mountain Labyrinth, The People of the Mountain and Giant Battle.
That means that out of 17 possible ventures in the game, only 5 can reward the 100% xp and loot; none of them available for players under level 58 for Snow White and 65 for the MCC ventures...
You must be reading something different to me all ventures that you can get from the excelsior through travel guides all of which you can buy in the merchant and available all year around when ever you like give the bonus plus the two book campaigns so in total 17 giving the bonus if your high enough to play em
Real shame I did The People Of The Mountain and A Giant Battle yesterday and eat up all my troops
Unknown regions has the event bonus.
When it comes to Gene pools and shallow ends they can be found at the bar drinking pina colada's
Well this is a pretty underwhelming event for players under level 58.