Pieces of Piston Ring in Intake?

2017 WRX 72k miles No Mods. No problems or symptoms until started up and engine made a terrible clattering noise.
Sounded like it was coming from intake manifold as if throttle body door was fluttering. No idle running rough. Took throttle body out and found chunks of metal in intake manifold. One piece looks like it is from a piston oil ring. Took off intake and found more metal sitting in intake ports at least three of them. Any thought on this?