This might be the aforementioned Reddit thread:
https://www.reddit.com/r/kindlescrib..._confirm_this/
No comments there for last 20 days. Not really possible from that sample to conclude it is an issue for all Scribes, though it's hard to imagine that the tolerance could be off by that much.
I just looked at my Oasis (9th generation) it has a gap around the glass, maybe 0.1mm. And of course it is waterproof. And yeah, I think I can see a little dust in there. But obviously it isn't going to get into the innards.
I think it is to prevent a hard edge knock from getting transmitted to the glass and damaging it. I can imagine that's why Scribe has a gap as well.