Out of sheer curiosity I sent the gun that 2 RM's broke in out to STI. This was also motivated by my switching back to a tungsten rod, and the gun feeling much flippier than with the RM.
They looked at it and did some slight machining of the spring tunnel, and flattened/squared the spot in the frame where the head of the guide rod goes. Apparently it had been bashed enough by other guide rods such that the RM did not seat properly, which caused flex in the rod, which caused bits o'RM to spew from the gun.
Whether it fixes the problem remains to be seen, but more than anything, STI has delivered great customer service thus far. Ed, the engineer of the RM, and Chris, the customer service manager, have both taken a personal interest in making things right, which makes the whole saga thus far easier to take. They provided their UPS account # for shipping, did the repair in one day, and even offered to refinish my gun free of charge (I kinda like it with lots of blueing missing). Also put several hundred rounds thru it and inspected it before and after.
Above all, they are honorable folks trying their best to solve issues with a new product that may not quite be the drop-in part that they had hoped for.