Why am I seeing ghost lines in Composer?

Hi,

I'm having an issue with actors' ghosts showing up in animations. The actors are set to 0% opacity throughout but in certain parts of the animation, their outlines show up (only the "smart outlines" and no colour). I've attached an image of one of the locations where this is happening. When I manually scroll through the timeline they sometimes appear and sometimes do not (even if i go back and forward without changing anything). I wouldn't mind this if it were just in the composer view but it exports these ghosts into the HTML version.

Thanks,

Ben

SolidworksComposer