Cycles render is blank and camera object changes I have this problem where my scene render is blank, and I think I've figured out why, but it's weird. 
I set my scene camera to the actual camera object:




But when I press f12 the render is blank. Not black, but transparent. Then for some reason, the camera object switches to 'bulb' by itself



Please help me out, this makes no sense.
 You can download the blend file here.
This is because the Bulb object is bound to the marker Jump. See this answer for details.

To fix it, you can either remove the marker (press X while hovering over it), or select your camera object and press Timeline header > View > Bind camera to markers (or press CtrlB in the timeline area).