Quark adds the ability to move tile entities using pistons. Moving a projector this way breaks the beam.

As soon as the piston is moved, it creates a default white beam at the destination. This ghost beam will never vanish, even after moving the projector and reloading the world. The ghost beam doesn't seem to do anything even if modules were in the projector.

After the projector is moved to its original position, it behaves normally.

Below is a purple beam that was moved back and forth with a sticky piston:

I made some improvements in 2afd178. I'm not completely sure how Quark works, so I'm not sure whether this is fixed. Please let me know.