Forums inside a category in bbPress: only first 50 forums are shown?


I created a forum with bbPress on my site.
I first made a category (named "template"), then created a lot of forums inside this category.
My problem is that only the first 50 forums inside this category are shown.
You can see it on the page forum (index):
(And inside the category of course)

I can't figure out how to fix this. Any idea?