Agreed this sounds like RAM: On the original MPU-200, the state of the METEOR drops is stored in the 24pin DIP 6810 RAM chip. On game powerup, it should be initialized to zeros, but if there was something wrong it might_ end up non-zero, and the software might_ reflect that state upon starting a ball. It would be a weird failure, one that I've never seen, but possible.

Not sure how the memory on an Altek board is done, but putting in an original MPU might at least tell you if it's the MPU or something else.

If a completely different MPU gives the same problem, it really can't be the 6810, so I wouldn't bother sourcing and replacing that chip.

This is a real mystery! I'm stumped.