When you drop a valve seat the chunks get caught between the piston and head. It does a good amount of damage to both but the outer edge of the piston gets beat up pretty good. Enough to compress the lands and pinch the top ring so it no longer floats. A ring that doesn't float will probably wear out quicker than it should.
As someone else pointed out - did you clean out the broken valve seat parts from the intake/exhaust and EGR?
Member of the Dropped Valve Seat Club.
Replaced #4 Piston, Rings, Rod+Bearings, AERA Re-Manufactured Cylinder Head and a light Hone. Then CLEANED the hell out of everything.