Hi
We have had this issue ever since we installed Community Answers a couple of years ago.
The Main Menu module (top) is set to display on ALL pages.
When the Community Answers component is activated the menu disappears, leaving a white blank strip across the top of the page where the menu position is. I'm not sure whether the menu is being disabled or whether it is just not rendering.
You can see it here.
I've had to kludge around it with extra menu items on the side, so it all looks a bit messy.
Any ideas for a fix?