I just had a two-hour head scratcher of my layer disappearing during rendering.
I’m working solely with vectors drawn and imported from Illustrator. I had one layer that would appear and disappear while my camera was tracking.
I don’t know what caused it, because I made sure everything was at the same z-height (I just wanted to operate the camera to pan & zoom).
The thing that made it all work was to click on every layer to render continuously. Problem solved. Two of my vectors resized after doing that (not sure why).