The character "热" in Source Han Sans looks bad in 15px 96dpi with fontconfig 2.10
(I'm not sure if this is a font issue or an engine issue, so x-posting here. Sorry if)
I've recently noticed that the character "热" sometimes looks very bad in my browser. It seems that this character at this specific size (15px or 11pt/96dpi) is rendered incorrectly with FreeType 2.10. The same issue also happens with Noto Sans CJK.
A reproducer and some screenshots are attached to the original bug report here: https://github.com/adobe-fonts/source-han-sans/issues/285