Quoted from Quench:Common problem now with programmers that use short program pulses with these old 2716/2732 EPROMs. You need to set your programmer to slowest speed mode (and double write if its a GQ-4X) so the EPROM gets a deep write cycle.
A shallow write cycle results in intended low (0) bits being too close to the threshold and once the 5V rail in the game starts to rise those bits start returning as high (1).
Doesn't help that a lot of the newer programmers may not use a high enough voltage to properly program a chip that wants 21V or 25V during programming