What is the display condition of the balloon icon for files that have comments?

In the past, when a “comment” was registered for a file or folder, a balloon icon was displayed to the left of the share icon on file list. I recently noticed that when I left a comment, the balloon did not appear. However, some files and folders have a balloon icon. A balloon icon is displayed or not displayed. What is the difference?

Nextcloud 18.0.2, CentOS 7.7, PHP 7.3.15, nginx 1.16.1, MariaDB 10.2.29

Can you please provide a screenshot, of a such a file or folder.

This may have been a misunderstanding on my part. That balloon icon seems to appear only when there’re “unread comments”.
I remembered that when I left a comment in my file, I still got the balloon icon. In other words, I may have assumed that the balloon icon was displayed even though it was a “read comment”.

Regardless of whether it’s unread or not, what is the best way to make the user aware of a comment’s presence without having to open the details panel if it exists?