I've got what I think is an odd situation. One of the pipes, connecting to the head, is loose. By that I mean I can pull it away from the head even though the flange portion that bolts to the head is solid.

It appears as though the pipe portion has broken from the flange because not only is it loose but, when the engine idles, I can see the light from the ignition.

Is this a common break?

 

It is common to have the tube steel headers crack at the junction between 1 and 4 pipes. I have not heard of cracking close to the head.