It’s good to trust your instincts. I don’t know the answer off hand, as I don’t use the CNC much. However, my first thoughts anytime it feels like there’s dust flying everywhere is to check the dust collection setup from the tool, through the hoses, all the way to the dust collector.
I’d look to make sure the dust collector is on, then check for suction at the tool end, insepct for clogs, kinks, rips, or other damage. Trace that back to the dust collector and ensure (in this case) the bag is inflated, the trash can has circulation, and there’s no hole in the bag spewing dust out in the air.
Someone else may be able to provide some tips on the actual flattening part, but this is where i’d start for any tool.