Version is 2.0.2 (Not listed under versions).

How to reproduce:
1. Set the SDL_Renderer to SDL_RENDERER_SOFTWARE.
2. Load a png to surface, then call SDL_CreateTextureFromSurface() to create the 
   texture.
3. Render the texture on the screen, and set the source destination to:
   x = 0;
   y = 0;
   w = sub-texture-width.
   h = texture-height.
4. Flip the texture horizontally, leaving the center point NULL.
5. Leave the destination width and height the same as the source width and height.

This will result in either a crash or a distorted texture:

https://i.gyazo.com/7a80f090c41afaf0068f2450c3e2512e.mp4

It doesn't seem to affect all textures. The snail hide animation only has 3 frames and works fine,
while the move animation (4 frames) seems to created the distorted texture.

With hardware rendering enabled, the animation looks just fine:
https://i.gyazo.com/3f1187ffd22c491ea1753732af627ce4.mp4

When I set the player character texture to render at it's native resolution, and loaded an image with 4 frames, the entire program crashed; giving me an access violation error.

The distortion only occurs when the texture is flipped and when the destination width and height match the original image's width and height (The sub-frame dimensions that is).
At first I thought I made a mistake somewhere (Since I'm pretty new to SDL), but since hardware rendering works fine I don't believe this to be the case.

I hope that this is helpful, and that I provided enough information for the issue to be tracked. I can provide the source if necessary.