My friend has mirrors texture problems with patch X and X10 (see attachment). Patch W without problems. He tried fresh X install too, different FOVs etc, but no success.
NVidia 6600 256MB, latest drivers, WXP
NVidia 6600 256MB, latest drivers, WXP

. He realized this when he was trying to change mirror LOD as you suggested, but this (changing mirror LOD) doesn't help.
), reinstalled Windows and LFS mirror glitch is away.