Low temp code with debris in thermostat

[thefiremeister]

Had a low temp code last year and reset it a few times and it went away it came back last week so I finally took the thermostat out and found it had some debris in it that looked like gasket material

Big chunks on the element side and pieces oozing through to the radiator side

Any one seen this before? Where could this material come from ?

06 Ram 5.7 Hemi