It's a good question. It could be that most people don't notice this things, those who don't don't report it, etc. Or maybe it only affects some people, but I can't think how that could be true. More mysteries
So, the only time the bug happens is for background updates that may be happening when the user isn't even present. And, since the CPU priority is low they won't harm responsiveness of foreground applications. But they will waste CPU time and electricity and battery life (if on battery). So, a silent waste.