I just had a most unpleasant thing happen. I was routing a mortise with my Festool OF2200 router connected to my Festool CT22 vac and during the process of making the mortise, the bag in the vac started on fire. Billowing smoke coming from it. Well, quick, out the door with that! The wood is new clean hard maple. No hidden metal, the bit is intact and it's tungsten carbide. What happened? I don't understand why it'd start on fire. I don't see anything to generate a spark. Yeah, I can see the fine dust in the bag being ready to go, but where's the source of ignition? And scratch one CT22 vac. That one has had it.