it looks to me like whoever cut the heads to accept those spring locators used a cutter that increased the diameter of the pocket, probably to about 1.640 or so(unless the OD of that locator is actually way smaller than 1.550).

as the heads come supplied from Indy, the pocket is only 1.550, and the small step at the base of the guide has too large of an OD for a locator to fit over it, so someone machined those heads to accept the locators.
also, if the springs you're using are actually like 1.560 or 1.580(also common sizes these days), then you can end up with a situation like what you have, unless the pocket is opened up to accept the bigger spring.

i have a customer that ran some SR heads with a roller cam and 1.550 springs in his S/G roadster for over ten years without anything to locate the springs other than the pocket machined into the head, and never had an issue with anything getting chewed up or ending up in the pan.

when i set those heads up for over-sized springs(1.625+) and/or spring cups, i remove the rest of whats left of the original pocket to keep those pieces from breaking off.

IMO, its not Indys fault you had this issue with the pieces breaking away from the heads, but rather whoever machined those heads for the locators and didnt trim away what was left behind.

when i have gotten heads from Indy that are already cut for the 1.625 springs and cups, all that extra stuff around the pocket is gone.

in any case.......just grind away whats left there, and you'll be good to go.