Thanks for the report. Do they maybe not seal "by design" to avoid the obligatory "thumping" when running with an IEM ? That could explain the "bloomy" bass to keep a pleasing sound in spite of the lack of a seal.
i also initially thought the same, but with my ears, they're not just form a seal and just sit there (like earbuds), but they are just outright dislodged
when i put it "just resting" on the ears, it does sound airy and not too boomy on the midbass. i would definitely try experiment with other eartips (maybe some foams) as i do like this other than the fit problem.
oo, and another thing, even with full seal, this one doesn't thump too much.. it's comparable to the Nillkin Go, as a matter of fact. i can eat and chew without hearing it loudly in my head. I'll try using it tomorrow for riding (bumpy road and helmet is my ultimate thump test) it still fit under my half face helmet. I'll report back tomorrow