[ART] Textures degrade after a while

[ToaOfJustice]

What is the bug? After playing TrackMania 2 (any title, but especially Canyon and Valley) for a while, some textures (especially those on the cars) become blurry.
How can I reproduce it? Play TrackMania 2 for a while. Observe the back of the car before and after degradation.
What is my expectation of this bug? Textures should remain at high quality all the time.

-My System Specs-

Hardware: 2.66 GHz Intel Core 2 Quad CPU; 4 GB RAM; DirectX 11; GeForce GTS 250
Screen resolution: 1920x1080 (native)
System: Windows 8 Pro, x64; Single user (with administrator rights)
Network/Internet: Local Area Connection, 10 Mbps; Firefox
Antivirus/firewall: Kaspersky Internet Security 2013

DxDiag log: Click here to download the .txt file..
NVIDIA System Information: Click here to download the .txt file.
Relevant Launcher Settings: Click here to download a collage of screenshots in one image.

-Toa Of Justice