Hi Malice tnx for replying. Cause of your reply I did some more tests and it only happens when I fire at a shade-c dynamic light while just standing behind its lightrange. The shade-c lights are valid targets in c_trace's.
I quess it makes sense when I look at the light create code, just suprised they didn't mentionend this in the examples cause its so easy so overlook (this could have created some many bugs lol):
ENTITY* spotlight2 = sc_light_create(vector(-156,-82,800), 1000, vector(2000,512,0), SC_LIGHT_SPOT | SC_LIGHT_SHADOW);
spotlight2.pan = 0;
spotlight2.tilt = -43;
sc_light_update(spotlight2);
As you see there is an entity created to support the light. My quess is this entity is the cause the bug so I am going to try giving it some flag or otherwise give it a .group number.
-edit, yes it works.