It feels like just yesterday we were arguing about whether the plastic clips fatiguing were user error, and now we're here.
FWIW and YMMV I have had the Hybrid since launch and run 10+ capsules a day. I have no melting/scorching of my housing (bags only no whip) and no dust. A cotton swap ran around the contact ring came back light grey with oxide. I did not have noticeable dust, large scratches, or dark grey swabs after cleaning.
Is it dangerous? There is research linking aluminum oxide and pulmonary issues in lab trials and in the evaluation of workers using aluminum-based abrasives industrially. These are quantities much larger than what we would be seeing enter our vapor path. That being said, exposure is cumulative, and it takes time and effort for the body to remove these oxides and it can cause fibrous regrowth including cancer. The research seemed to suggest the removal of only 9% of the oxide each month. The oxides also are shown to migrate to other tissues from the lungs.
The device works by having contact between the aluminum rings but I would say don't make it tight. I get plenty of conduction for extraction with a light twist. Is it user error, is it a bad design? I'm not blaming anyone or demonizing S&B, although I am disappointed in their less than premium response to a premium item. It may be fair to say the Hybrid convection rings work safely unless a bit roughed up, and there are issues with the housing material between batches.