Operating system: Linux x64
Graphics card: GTX 860m
Any of the 2.80 daily builds I tried since several months ago.
Short description of error
Using Cycles with a fisheye lens camera, both Equisolid and Equidistant, and some texture with Window projection from the Texture Coordinate node flips the X-axis of the texture.
None of the other lens and projection types behaved like this as far as I saw.
Here's a render with perspective (top) and fisheye (bottom) illustrating the problem.
And here's a small .blend file. Set the view to Rendered and the camera lens to Panoramic.