It kind of looks like the problem with the missing center of the car light streak may be related to totally blown white in one of the images. It kind of makes sense that the HDR software would try to put something in there.
Can you post the two original images?
Thanks for your help. Here are the 2 original images, taken one after the other. Of course, the second one does not have the streaked out car light. I took it purely for the sky.