Anti-aliasing / hinting along straight edges in separator glyphs?

[MIvanchev]

Hey, today I had the following issue while building up my tabline:

The glyphs I use are U+E0BA and U+E0B8. You see the glyph of E0BA renders with anti-aliasing along the straight edge while the other glyph does not. This seems to be quite bizarre. The font is Literation Moto from https://www.nerdfonts.com/font-downloads. I didn't make any custom modifications. I've also spent considerable time checking the settings of my OS (Ubuntu MATE). I think this might be a Qt problem but I need your help. Do you have some clues?

[equalsraf]

No idea honestly.

I see antialiasing is explicitly enabled when drawing an undercurl, but in no other case. Is it possible this is not antialiasing related, but rather some other type of clipping issue at the edge of the cell.

[MIvanchev]

Hm, the issue seems to exist outside of neovim-qt as well so probably related to the way the system is handling font rendering... Damn that's gonna be a tough one :/