Something wrong with UV on Sprite (2D) ? - bug?

TypeOverride

I used this shader code for testing the UV because it doesnt seem to work. With vec4 texture_color = texture(TEXTURE, UV); is everything fine. He is showing up the texture. But "rainbow colors" with UV is not working. Its only blue (brighter blue). Here is how it should be look like (but it doesnt look like this):

TwistedTwigleg

I could not reproduce the bug, I always got an image like above.

The only time it didn't work was when I was using a region instead of the full image/sprite, in which case it only showed a small section of the image above (and was generally only blue). Are you using a region?