I don't know if it happened to anyone, but seems that many of the lights that I assign to be primary_spot disappear in game when looking directly at them or getting to close. Its odd, so you can turn around, wait for some seconds and turn fast and see how the light disappears fading really quick, is like they are hidding from me. Any clues?

If you place a light and a info null, select the light then the null and press "W" it will connect them to create a spotlight. Then you can change the intensity of your light and exponent. I am a beginner with lights but i noticed that exponent 0 gives a more defined shadow , and 1 gives the shadow still but in slightly less defined. The shadows go directed to the info null so it is best to place the null where you want the shadows to appear. In some areas of my map i added the null to the wall at a higher point and the light lower to cast the shadow in that direction ( running along wall etc )

This helps http://wiki.modsrepository.com/index.php?title=Call_of_Duty_5:_Advanced_Lighting , the light i have used a lot of is a spotlight targeting info null, exponent 1 , fov outer 120 , fov inner 65 , intensity depending on area but a have not got any at 0 , and light_point_linear seems to be the best one for shadows. I usually have my lights at 350 - 550 radius.

I have areas too in my map where the shadows seem blocky until i focus the screen on them closer , try using caulk shadow on the areas where you have caulk. Example inside a doorframe you would have caulk on the inside faces where the player will not see that texture, when i used caulk the light leaked through and when caulk shadow the light was nicely blocked. I would guess  the shadows are trial and error depending on your map size , room size etc. One more thing i did was somehow changed my world spawn colour to red, so all the dark areas of my map turned into a red tint , so it may be worth backing up your map file and checking if your colours in worldspawn may have been "accidentally" changed like mine lol . I think once i ended up with a zombie_cost in my worldspawn too lol