ImNotLaffng Did the bug have to do with how the PD shots were spawned, their hitboxes, or general game physics tomfoolery?
There's a modding feature called SourceShipCollisionDelay that, if used, prevents the shot from colliding with its own ship for a certain amount of time after the shot spawns. But there was a bug where even if you don't specify a SourceShipCollisionDelay there would still be one frame where collisions with its own ship would be ignored, and a PD shot can actually travel pretty far in that first frame.