this is happened when i open the folder, and sometime i got freeze on my system, and the page app indicator turn into many as this video : folder and app page dot indicator bug on ubuntu 20.04
This bug has been reported here Gnome Shell completely freezes in Ubuntu 20.04 when clicking outside of app icon folders. The cause of the problem is the Ubuntu Dock extension. I solved the problem by changing an extension setting.
How to solve:
sudo apt install dconf-editor
Deselect the "Use default value". And set "Custom value" to "False".
There's a video here showing how I did it bug: application's icon folders.