The issue you're experiencing with the comments box in the Edge PDF viewer, where the font appears differently while typing compared to the final result, may be related to specific rendering problems. According to the known issues with Microsoft Edge, some text isn't displayed correctly when viewing certain PDF files, particularly those containing Japanese fonts. This could potentially affect how comments are rendered in the PDF viewer.
If you're encountering this issue, you might consider enabling the new Adobe Acrobat powered built-in PDF reader, which could resolve some rendering problems. Additionally, ensure that your Edge browser is updated to the latest version, as fixes are regularly released for known issues.
For more specific troubleshooting, you might want to check if the issue persists across different PDF files or if it's isolated to a particular document.
References: