Night time skybox glitch

So, I have played a lot of Black Mesa but each time I get to the outside area of On a Rail, or a multiplayer map that is night based, I see that really cool realistic effect on the stars that makes them blink but, after some time, they just stop blinking and are only doing it when I the player move its kind of upsetting.

Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valveā€™s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.