Metallic rattle

Hello everyone. I finally ran out of options and I cannot figure out what is rattling around my exhaust. I checked heat shields and nothing is loose. It only happens around 1700-1800 rpm and it just rattles and sounds raspy. I have a 2015 4.0 liter v6 Tacoma. If anyone knows what could be happening, please weigh in.

 

On mine, the weld where the hanger post section meets the exhaust separated under the center to rear passenger side. You couldn't 'see it', but when under it with it running putting pressure on that point of connection would stop the rattle.

 

Might even be the guts of the muffler are loose .

 

Yep, probably one of the internal baffles