When I rotate my camera down vertically to about 60 degrees it seems to hit some resistance and stop. Then when I attempt to rotate it back up it hangs for a bit and them pops free and jumps up to level. When I'm rotating down I can give it a little nudge at that point and it will continue down to 90 degrees but then when I try to return to level it hangs there at about the 60 degree down point until I give it a little nudge to get it going back up. Any ideas on what the problem/fix is?