Hi Steve,
I had one stick on me like that and it was no fun getting it out. In my case, it was caused by a small rusted out piece in the perforated section of the baffle that had bent out just enough to cause havoc with my attempt to remove the pipe.
Since I didn't intend to save the baffle (super rusty), I just drilled a hole through the outer section, slipped in an equally expendable screwdriver and proceeded to pound the heck out of it till it finally came out.
I wish you better luck. (below is a pic of the section that rusted out)