I have a part between the cat and the muffler (not the rear resonator just before the tailpipe), which looks like it could be an extra resonator - but I can't seem to find any reference to this part on various parts diagrams.
The pipe on the muffler side of this mysterious part has become detached right at the part - it looks like possibly faulty welding. I'm guessing the pipe could be re-welded to the part - both of the pieces are in fairly good condition. I floored my machine whilst passing and at that moment the engine noise became much louder - I knew I blew something in the exhaust.
See this photo composite I made to illustrate. The image on the left is the muffler, the image on the right is the cat, the piece in the middle is the one in question. You can see the pipe joint that's come apart -- I just re-aligned them by hand best I could.