This has been reported before and can be easily reproduced. I've never heard that it's any kind of special feature - I'm with you: Bug.
I suspect because it's a preview-only problem and doesn't affect the image quality, and it's kind of nonsensical operation anyway, Adobe has assigned it a priority level below that of pretty much everything else.
But if it were my software I'd certainly be embarrassed that it does that.
Thank you very much, Noel.
I had searched the forum without luck so I'm happy it has been reported also, as you said, it won't probably get fixed any time soon.
Have a great day!
You're welcome. I just did a few searches myself and didn't turn up the conversation. I think it was at least two years ago!