Steps to reproduce:
1. Write a list of 3 or 4 names in a text editor (i.e. Notepad++), i.e.
2. Navigate to a CKEditor (i.e. status update, blog, forum, etc.)
3. Type a "@" symbol in editor.
4. Copy and paste the first name, i.e. "Test User1" immediately after @ symbol.
5. Select the resolved name from list.
6. Either add a space or return to a new line to add next @mention name
7. Type another @
8. Paste in the next name "Test User2" from your plain text editor.
9. As soon as it's resolved, the first name above will change from "Test User1" to "Test User2".
10. Add a space or return to a new line, and add another @ symbol and immediately paste in the 3rd name .. and the top entry will change again!
Connections Dev has indicated the inability to copy/paste an @mention for Connections onprem is a limitation and has been noted in previous cases. It continues to be a permanent restriction for Connections onprem.