I also found this: Bug:MC-51953
That's not a bug, that's basic projective geometry. That's how perspective projection works.
You know what, I'm pretty sure that your motion sickness is because your FOV is too high. To have a perfectly non-distorted view, you need to adjust your FOV to the exact value of the angle between the top and bottom edge of your computer screen (measured from your eyes), because that's what FOV means. If your FOV is set to that angle (or alternatively if the angle is changed to the FOV value, by moving closer to the screen), if you close one eye it should seem like your monitor is literally a Portal-style portal into the virtual world behind it, with no visual distortion. That's because that's literally the exact calculations your GPU does.
EDIT: Need another intuitive explanation? Suppose you imagine the sun as a square sticky note in meatspace, circling your head and always facing you directly. If you hold the sticky note in front of the center of your computer screen, it will block a square area of your screen. If you move the sticky note (rotating it around your head) so it blocks the right edge of the screen, it will cover a "rectangular" (more like trapezoidal) area, and that area is bigger than the other area. If you move your head closer to the computer screen, this effect will become way more pronounced.
Now imagine you make the sticky note half as big, but hold it half as far away from you. From your perspective, nothing changes visually (except some lighting), and the sticky note will cover the exact same pixels it did before you scaled it, no matter where it started.
Now imagine you make the sticky note 1234567x bigger and hold it 1234567x as far away from you. Now it should be waay behind your monitor instead of in front of it, so the pixels that used to be blocked by the sticky note are now exactly the pixels
blocking the sticky note instead.
Now remember that 3d rendering is made to look like a completely undistorted window into the world ((if your FOV is set correctly)), so if you move the huge-ass sticky note into the virtual world at the same relative position as it was in the real world, those pixels
blocking the sticky note are now exactly the pixels
displaying the virtual sticky note! And that's why the sticky note is rendered askew when from an angle.
tl;dr: Your computer is doing everything right, but you liar told it that you're sitting like two inches away from the display. Don't blame the computer.
EDEDITIT: I can't believe nobody in that bug thread realizes this isn't a bug. Everything is working perfectly as intended. Even that 5760x1017 video looks exactly as it should look according to projective geometry. The only issue is that the fella isn't close enough to his computer screen.