Don
I've never seen the chip your asking about?
Values $1, $5, $25, etc. were made first and probably shared a single set of printing plates. The centers on all these values had a background that was more yellow/gold. The 50 cent chips made in 1966 & 1967 would have been printed on a different set of plates. It's likely the printer mixed the ink wrong, shifting the color more to the orange?
jim