I have tried uninstalling and reinstalling both traditional and simplified Chinese in my Windows settings. I have checked my font settings in Chrome and there are no options for fonts in languages different from the UI/System language, which in my case is English. This issue persists in some apps (such as Discord) but does not persist in other browsers such as Firefox or Opera. I do not have any custom fonts installed for Chinese. I am on Version 4 Build 19044 of Windows 10 and running the latest versions of Google Chrome (Version 1.114) and Discord (Stable 138254 (8e7d809)).
This started today () and I have not made any changes to my font or language settings since about a week before this started happening. On Yabla, the search box renders 在饭馆 with 在 in traditional and 饭馆 in simplified:
On Duolingo, we have two different fonts in the same sentence: On Google Chrome, Chinese characters are being marked in different scripts on the same site, and traditional characters are rendered in a sans-serif font while simplified are rendered in a serif font:
