Presumably being a real 72 Tele Deluxe, it was down to Fender's poor build and QA standards at the time. For example, the 3-bolt micro-tilt neck arrangement only worked if the parts were produced to a tolerance that Fender were unable to consistently reproduce. Some worked, but a lot were very loose and would go out of tune if you looked at them.

Tokai showed them it could be done in the '80s with their copies of '70s style Fenders with 3-bolt necks. The modern Fender reproductions also now work consistently.