I think you can turn this behavior off. From the control center, go to launchers & menus, then set it back to the old setting.
That said, I haven't found it a problem personally, and I do spend a lot of time on the left side of the screen. You have to push to get it to show, so I've found it hard to activate it by accident. Actually, I don't like that you can still also show the dash with the BFB, since I always hit that instead of my browser's back button but then, that's what preferences are for.