Bandolin, the Geopoly tool will arrange the selection of polygons or edges into a uniform geometric shape (a rectangle to a square, for example).  Try it again on another object.  This time, make sure you have exited the Inset tool entirely.  If you inset, then switch over to Geopoly and click it while the inset tool is still active, the result you experienced will occur.  My guess is that you still had the original Inset command activated when you selected the Geopoly tool.  Make sure you have dropped the Inset tool first.  I just tested it again on a sphere, and it worked as expected, but if I Inset, then switch to Geopoly without dropping the inset tool, it does what you described.

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