Heard back from Topgreen, they assured me the silicone used is all food grade, what is wrapped around the oven as seen in the photos may be the same as in the mouthpiece and seems like it is probably the same as used in the xmax v2 pro? It does seem neutral there and in the mouthpiece after soaking, issue is you can't soak the parts touching the I've around and inside on top, so hopefully it eventually neutralizes from the burn offs?
Airpath wise it should be pretty isolated too, but there are slight gaps and crevices where the construction comes together, so with air intakes blocked that is why it can come through usb. In normal use airflow probably takes path of least resistance and is fine, I am a little concerned about vapor getting over the electronics though... In any case they will look into this for the future making more airtight seals so that's good news.
The fumes could just be visible hot air now that they are so slight, but I'm not sure since the smell isn't gone yet either. Would be nice if someone else could test and compare with me, but seems everyone else used they're units without checking that? Didn't notice smells like I did? I can check with the second unit, though it certainly smells the same...
I'll keep updating if anything changes, would like to be able to try it with herb myself some day, but we shall see