Mine had at various time, until I threaded the rod on the exhaust just in front of the rear tire. Then I put a locknut on it. This stopped the exhaust from moving around and sometimes falling off of the isolator.
You need to get under there and bend your frame hanger and hanger off the exhaust. I have the perrin and lowered 2 inches and got some rattle. Solid motor mounts and some bending got me rattle free.