Visualization of textures in inventory

Try turning off anistropic filtering or mipmapping. One of those is the likely cause. Your video card/drivers may not support them correctly.

Is this still a concern in the current Minecraft version 14w07a / Launcher version 1.3.9 or later? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.

Working as Intended. Mipmapping and anisotropic filtering also affect creative inventory.

Intended.

You've already said that, but this one is ambiguous enough that we'll leave it to Mojang to make that decision.

Look at this MC-57574

That's a significantly more convincing argument.

😉