You're certain that when you tried it in custom, you used the exact same add-ons? A console trace over the span of time where they spawn would be the most effective, since nobody is gonna install all those add-ons to try it themselves. If I were to take a wild shot in the dark guess from the add-ons list alone, maybe Script_HitLocations, since I've known some scripts like that to work by shooting a paint projectile at the player and seeing what part gets colored.
On an unrelated note, you apparently have a client add-on in there.
On another unrelated note, is this actually a coding help topic? Without any actual code to fix it feels like a normal add-on conflict help thread wearing the skin of coding help.