Created attachment 151784 [details]
This might be a flexbox bug, but I think it's more likely an outline repainting bug. In the attached test-case, the blue outline-top only paints the bottom 1px of the 5px width.
Created attachment 151785 [details]
better test case
Actually, this looks like it might be a flexbox bug.
It looks like this works as expected in chromium beta & canary. Maybe it has been fixed by another patch?
Yeah, works for me too.