1.  Version: 21H2   Build: 22000.675

2. Version 1.24

3. Single Line.  I'm not sure that answers your question.  If not, repose your question.

4. 100%  1920x1080

5.  I have only four taskbar items: Thunderbird (Mozilla), Firefox, AB Commander (file manager) and NotePad++  When the icons are missing, they are all missing.  That is to say, when they first disappear, they ALL disappear.  I can only restore the icons one at a time by starting the app by clicking on the empty space.  That ALWAYS causes the icon to reappear.

I have not been able to identify any pattern regarding when the icons go missing.  Only the taskbar items are affected; all others behave normally.

I hope this helps.

My settings menu is different than yours.  I have no setting for taskbar size.  You can see my taskbar in the screen shot in my original post.

I answered your question about recreation in the second paragraph of item 5 in my previous post.

You final question does not make sense.  Get someone who has a better grasp of English to rewrite it.

As I have stated, I do not know what triggers this problem.  It just happens once in a while.  I doubt there is anything you can do to fix Start11 other than looking at sections of code that might contain the bug.

I never use Explorer so I don't know if running it would fix the icons.  Certainly doing a reboot fixes the problem.