There was a bug in 2.6.7 regarding page layouts, so give 2.6.8 a try and see if it’s better?
Well, even with 2.6.8
Settings for the forum page:
I see now, thanks!
Perhaps, this is something that bbPress could do a better job with. Each of the forum/topic type pages is its own thing, and they do not inherit the page settings from the forum root in the way it seems like you are expecting for them to – which is totally reasonable to expect.
That’s a bad new for me, I hope the inheritance will be added 🙂