If I am not mistaken, using the mustard chips in your scan as an example.....

The manufacture first creates the mustard chip as a disk. It is notched with the two "V" shapes. A matching "V" shaped insert (one flourescent green and one magenta) is placed into the notch-outs. The inlays are then placed and the assembly is put into a mold. Heat and preassure are then applied. The the inserts and chip body fuse into one, the inlays adhere to the body and the mold pattern is pressed into the body (both sides).

Lets suppose that one of the "V" inserts was not produced in the right size and it's volume was less than the volume required to fill the "V" notch in the body of the chip. Because of the fusing process (actually melting the chip material) and the aplication of pressue (a lot of it!) excess body material will flow-in to fill the void of not enough insert. Insome cases, like the chip on top in your stack, the excess material completely covers up the edge of the insert.

I would imagine that if you were to drill into the edge of the chip, at that insert point, you will find some magenta material just below the surface of the mustard.

I hope this helps.

Jim Follis