GerberPanelizer extremely slow in GerberTools_2020_7_30 release

while GerberPanelizer from the GerberTools_2020_7_30 release takes seconds to minutes to export a panel, GerberPanelizer from the GerberTools_2019_9_20 release takes hours to days for the same panel (depending on how many instances there are).

Happens under Windows 11 Pro