Issue Summary

This is reproducible on Data Center: yes

Steps to Reproduce

1. Create a test Issue
2. Add a comment on it with:
   "Hello [@add a mention to a user]Unable to render embedded object: File (  Hi There) not found."
3. Click on Add
4. The text in the comment is now:
   "Hello MikaelaUnable to render embedded object: File (  Hi there) not found."

However the error is occurring only with:

• double spaces after the first exclamation
• If before the first exclamation there's a mention to a user
• If the second sentence has more than one word (and an exclamation at the end)
• Error occurs in Firefox and Chrome, works fine in Safari

note: recreated the error with 8.16.1 and on latest 8.22.2

Expected Results

The error "Unable to render embedded object: File" should not be displayed.

Actual Results

Error between the phrases:

"Hello MikaelaUnable to render embedded object: File (  Hi there) not found."

Workaround

Do not use double space between the phrases