Bold formatting kept

[nico3333fr]

Describe the bug

Hey, I'm one of the Proton Mail devs, we are using Rooster and we spotted an issue.

To Reproduce

Steps to reproduce the behavior:

1. Open Rooster
2. Write some content, put content in bold, red, 24px text size
3. Go to the end of the line previously formated, add a few new lines
4. On this last line, remove bold, red, go back to 14px text size
5. Paste some unformated content

Expected behavior

I should see the pasted content in 14px with no bold/red.

Screenshots

Content is put in bold.

It seems the b tag is kept even if I did click on the bold button to remove it.

I reproduce similar issues on https://microsoft.github.io/roosterjs/index.html

Thanks for your help in advance :)