Using script Iconset Maker. (which will delete a folder if present and create a new folder)
Navigate into folder which has saved format grouped ext(dirs), looks something like
click the button to make iconset, works okay but folder is not grouped properly, it looks like this
no folders group, scrolling up & down is glitchy
collapsing the groups reveals this

the bottom Unspecified will not expand when double clicked, and the top Unspecified expands to all the PNGs.
Clicking Refresh fixes the issue
UPDATE:
version 13.0.39
issue is still present except the new folder is being sorted at the bottom of the groups instead of at the top. (a refresh fixes)