After using Pop!_OS for about a month the icons inside a GNOME folder shrank. I re-installed it and have not been able to duplicate the issue. However, now on my Fedora 33 install the same issue occurred.
In my Applications Launcher I created folders. Only in the folders with more than 9 or 10 items has this occurred, but the icons became much smaller. This is how it is in all my folders with more than 9 or 10 items. Both pictures were selected using the edge of the box the icons were located.
the difference in that issue and my issue is that all icons are not shrinking. I put all my games in a one ‘folder’ and all my ‘utility software’ in one folder. If I put more than 9 items in these folders, the icons shrink. Otherwise, all the other icons remain the same correct size.
As you say, if you put more than 9 icons in the folder they shrink, but only a little. That is so dots across the bottom can be displayed as a forth row for your use in selecting the different panels added for the additional content without panning the icons inside the folder.
The thing is I put about 12 icons in it, it works fine, and after 2-3 weeks the icons shrink. They do not shrink the moment I put the icons in there but after weeks of use.
Also, all folders with 9 or more icons will shrink. As you see in the pics that I attached. Both have the same amount of icons in them. After a few weeks, it shrinks. Removing icons does not increase the size either… I can take all but one icon out, and it will remain tiny.
My only solution is re-install and not put more than 8 icons in one folder. It’s really just a nuisance.