Hello! I'm a total Houdini newbie, so if the answer to this obvious, I'm sorry! I'm trying to make a tire that follows a path using clustering, so I thought the easiest way to do this would be to change the sources given with the sky trail shelf tool and allow the simulation to combust. This mostly works, except one cluster randomly minimizes as soon as it is required in the middle of the path (after the third box appears). This does not happen while the simulation is just smoke with no fire. Any ideas what could be going wrong?