So far I have observed this when people use:
Logic blocks (specifically buttons to trigger logic drives and possible logic clocks in general)
Rail Dockers
Visually me and several others have observed when these are used they visually output:
Salvage Beams
Cannons
Damage Beams
It appears to only occur when a ship is equipped with these weapons, however it outputs these effects visually when they should not.
I have only observed this on multiplayer unsure if this is present in singleplayer