Adding an icon like (?) on additional @mentions behaves unexpectedly in the editor and ultimately doesn't save.

Issue Summary

When adding an icon like in front of an @mention on a Confluence page works as expected. However, when adding a second @mention and saving the page, the icons/emojis are not able to be inserted properly when editing once again, and are instead inserted into the @mention itself. When saving the page again, the icon/emoji is not saved at all.

This is reproducible on Data Center: yes

Steps to Reproduce

1. Step 1. Add an at mention to the page and add an icon in front of it.
2. Step 2. Add another at mention and save the page, and then edit it again.
3. Step 3. Add another icon in front of the second at mention.
4. Step 4. Step 4. Save the page.

Screen recording of behavior: Mention and icon test.mp4

Expected Results

You should be able to add an icon/emoji before another @mention.

Actual Results

The icon is not able to be inserted properly, is inserted into the @mention, and ultimately isn't saved at all.

Workaround

Adding some text in front of the @mention first will allow you then to add the icon or emoji.