We've been getting a lot of bug reports about it recently, though it's been a thing for a long while now: If you're in a group, everyone in your group will see you hide and some other stealth actions by default regardless of skills and rolls. This is by design, assuming that group members are deliberately coordinating with one another to know where everyone is to achieve effective group tactics and such. This may change, but it is by design and not a bug. Feedback is welcome on the subject.
If low-perception characters are consistently seeing NON-GROUPED high-stealth characters every single time, that would be a bug. (Though another one players often report as a bug is when they keep getting seen because they're carrying a light source around with them. This is also by design. Don't carry a lit light source around if you're trying to be stealthy! Yes, this makes completely-dark areas a pain. They generally are.)
PSA: Group members see your stealth actions
PSA: Group members see your stealth actions
<Rias> PUT ON PANTS
<Fellborn> NO
<Fellborn> NO