How to edit and replace comments on File Exchange submissions?

It's a hidden algorithm that controls what happens when I write comments on my submissions at File Exchange. I failed to find a description of the behavoir and I'm frustraded.

Examples from m2uml

4 Mar 2021: I intended to write two comments, two to keep issues separated.

1. I wrote the first comment and clicked [Save]. The comment turned up in the top of the list of comments up and in in my Activity Feed. So far so good.
2. I wrote a second comment. I didn't notice any sign that I was editing the first comment. I clicked [Save]. The second comment appeared at the top of the list of comments. I can't remember whether the first comment was still there.
3. A couple of hours later I noticed that the first comment was missing.
4. I recontructed the first comment in an editor. I copy&pasted from Activity Feed and some source code.
5. I copy&pasted the recontructed first comment into the [Comments and Ratings] box, which was empty, and clicked [Save]. The second comment was overwritten.

4 Feb 2021: I intended to add text to a comment. I better be short because my memory may fail.

1. I wrote and [Saved] a comment.
2. I believe that the text of the comment appeared in the [Comments and Ratings] box when I selected the box.
3. Three hours later [Activity Feed] I wrote some text at the end of the comment and [Saved].
4. Result: two comments, the first without the added text and a second with the added text.

What am I doing wrong? How is it supposed to work?

In response to the comment of @Stephen Cobeldick

5 Mar 2021a: I intended to [Save] the second comment of 4 Mar 2021

1. Refreshed the m2uml page (to be sure)
2. I copy&pasted the text of the second comment to the empty [Comment]-box and [Save]
3. Refreshed the m2uml page. The second comment was added without affecting the first comment - as expected by Stephen.

I switched to Microsoft Edge. So far I had usef Firefox.

5 Mar 2021b: I intended to test editing.

1. I wrote the letter "a" in the [Comment]-box and [Save]. The new comment appeared in the top of the list.
2. I "clicked the cursor" in the [Comment]-box. The box remained empty.
3. I wrote the letter "b" in the box and [Save]. The new "b"-comment replaced the "a"-comment in the top of the list.
4. I closed the m2uml-page. Now the "b"-comment is permanently(?) in the list.

Conclusion: I failed to edit the "a"-comment.

[Stephen23]

My experience is that a comment is updated/replaced until the page is refreshed. This means:

• you can keep making changes to one comment, clicking add multiple times, as long as the page is NOT refreshed.
• to add a new comment you therefore need to refresh the page.