All the windows on Big Sur have noticeable white line on the top

In dark mode, there is a 1px white line on the top border, this should be fix like other three borders.
Easy to re-proudce: 1. Turn on dark mode, 2 Open Finder, Music, Safari or any other app, 3 Focus on the top of the window.
All the windows on Big Sur have noticeable white line on the top
 
 
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