The warning image ⚠️in my Obsidian (using light mode with the default theme) is a black background with white exclamation point ... see the screenshot ... I opened the document in Typora and it shows correctly there. So it has something to do with Obsidian.
![image](https://private-user-images.githubusercontent.com/20246623/302617877-25d99553-09aa-4070-8f83-2df8648d77e8.png?jwt=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.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.3whCuwTZPoTgI7Cyl584Kh0ZonLANllCFDy27Y8tgHk)