This was discovered while testing the changes in MDL-46497. That patch improves the existing behaviour but there is still one small bug left to squash.

The steps to reproduce the issue are:

1. Enable RTL/LTR buttons as described in testing instructions
2. Create a new course
3. Paste "אני כותב בעברית And also in English וחוזר לכתוב בעברית" into the course summary
4. Highlight the text and click the right-to-left button (you have to click show more buttons in atto)
5. Toggle atto to raw text mode by clicking the "<>" button
6. Toggle back to HTML mode by clicking the "<>" button
7. Click the left-to-right button
8. Toggle back to raw text mode by clicking "<>"
9. You should see a redundant <p> tag was added
10. You can keep adding more redundant <p> tags by toggling to raw text mode and back again, then clicking the left-to-right button. Each toggle and button combo will add more tags.
    • Note: When reproducing this issue you should only be clicking on the buttons. Don't change the cursor position or highlight the text or anything