This behaviour was not present in V12,
the video shows process of making an iconset with iconset maker,
In the folder are 2 iconset folders of 2 different sizes.
if a folder with same name (name is made from iconset name and the 2 sizes) exists it is deleted, then a new empty folder is created with the same name, then the script finishes making the icon set and puts produced files in the new folder.
In the video the lister jumps to the bottom, (it did not do this in V12), I think because it has placed the new folder there but the new folder is not visible, I scroll to the top when the script has finished, the new folder is not there, pressing refresh and the folder appears.
similar behaviour happens when not grouped, except the new folder is the last item in the lister and pressing refresh puts it where it is supposed to be.