It's an LOD issue. Either the LOD for that distance is messed up, or the texture for the model doesn't have mipmaps and it doesn't have a fallback.
For issue 1, go into OpenBRF and generate LODs.
For issue 2, go into your texture editor of choice, open the original texture file, re-export it as the DDS with your compression of choice and make sure generate mipmaps is enabled.