I totally see this with premium novels and comics, where Tapas seems to pick a particular idea and then grab a bunch of it. I don't understand this, but I don't read much premium stuff (though to be far I checked on of these out and ended up liking it way more than I expected).
This isn't nearly as true of the community novels and comics, though. There's always going to be certain things that are popular, and so rise toward the top, but it's more varied. Tapas can still promote certain things if they want, but I think largely this is just.. what's popular with people. I'm picky, so I only really check out the specific things that interest me, so if there's a bunch of the same at the top of every genre within the community stories, I have not noticed. XD
Well, at least Tapas enabled us to pick more than one genre now? So while you have to pick a main genre, you're not as limited as you might have been. Plus there comes a point where listing too many genres, even if you technically touch on them, would not be helpful to readers looking for things.
I have two thoughts about this... firstly, try to address it in your series summary. Heck, even outside of the series blurb, you could add something like "A genre hopping tale of fantasy and mystery!" But also... there's nothing wrong with surprising your audience. Even if they come with certain expectations, subverting expectations can totally be a good thing.
Yes- I prefer mixed genre stuff!
I think there's still improvement needed, but the recent changes (picking multiple genres) is at least a step in the right direction. To many options can also be a problem, but I think a better search system would go a long way.