Symmetry and kerning issues with hinting on Linux

[CendioOssman]

First off, thank you for a generally very nice font.

We have one issue, though. And that is that hinted glyphs get distorted in a bad way in some cases.

Hinted:

Unhinted:

As you can see, the "T" loses its symmetry, and the "L" doesn't have a clear separation from the "i" any more.

I'm uncertain if Poppins has any hinting. I don't see any change when enabling FreeType's autohinter, so I would suspect not. It seems to be struggling with hinting in general, as no stem is particularly sharp in the hinted case.