The heads are hand painted by many different people so how would anyone seriously think every head paint job is going to be perfect. ?
No one's asking them to be perfect. Common sense approach is that as soon as a problem is found, then the defective part be put aside and and replaced with a "passed" item.
In the case of the Gene Simmons heads - Whoever painted it, should have thrown it in the bin or sent it back to be repainted. If the trend continues - fire the moron that cannot follow simple lines. Better still, why Can't Stern work out an automated way of painting the heads ?
In every other manufacturing process, QA should be at the component level and then at the completion point. Whoever fitted that head needs to be fired or given an eye test. Whoever allowed the machine to be placed in a box and shipped needs to be fired.
Using the car analogy - Ford used to remove a completed car off the line and then strip the machine bare to see if there were any re occuring manufacturing problems. Every industry has QA. It seems Stern don't.
How the hell this can happen is highly embarrassing - That's why I'm finding it hard to believe.
