Windows 8.1. When the window is maximized its a bit better but still blurry on the edges. Watch the screen, of startup window size, in original size or you don't see it.
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I'm sorry I've got the wrong impression, but still, I cannot reproduce this on a normal environment.
EDIT: This bug has been fixed in the latest builds: https://aemetta-toasteater.itch.io/lavakinemat-inc/devlog/82123/fixes-to-windows-specific-bugs