A player on my server had Jpipes setup with a quarry and furnaces with it all piped to a coffin.  He noticed that after the quarry stopped running and the furnaces cooked all the metal and sulfur he was getting 200 sulfur for free every tick.  There were no boxes in between the 3 empty furnaces and the coffin this went on for a day or two so he removed all his jpipes, furnaces, and quarry to see if that would fix it but still had the 200 sulfur every tick.  I unloaded jpipes and it would stop and when I would load jpipes it would start again.  The only way we found to stop it was to remove the coffin and put it back down then it stopped.