I think you must be referring to this posting? I haven’t tried any others in Gramps. Here are the contents of that KML file:
\<?xml version="1.0" encoding="UTF-8"?>
\<kml xmlns="http://www.opengis.net/kml/2.2">
\<Document>
\<name>farm\</name>
\<Placemark>
\<name>farm\</name>
\<description>Brady farm\</description>
\<Polygon>
\<outerBoundaryIs>
\<LinearRing>
\<coordinates>
-78.727697,44.299047,0
-78.711711,44.302832,0
-78.709429,44.297504,0
-78.725496,44.293817,0
-78.727697,44.299047,0
\</coordinates>
\</LinearRing>
\</outerBoundaryIs>
\</Polygon>
\</Placemark>
\</Document>
</kml>
I will have a look.