Odd, works fine for me.
Try the following commands and let me know if they work. You can make one into a macro if so until the nightvision button is working again.
/r_flat_ambient true (
FALSE to turn it off.)
This is the command the Nightvision button uses.
/r_min_dir_ambient_intensity 0.8
/r_min_dir_ambient_intensity 1
/r_min_dir_ambient_intensity 3
/r_min_dir_ambient_intensity 10
This is the game's Minimum Ambient Light slider. The slider only goes up to 0.5, you can use higher values via this command. Greater than 1 gives some lighting bugs on distant objects. 0.8 is what I use.
Hope these help.
