Just tested it and found a couple of problems with the GPX file.
The first is that they are not valid XML
GSAK is inserts the line below in the xsi:schemaLocation to make it valid XML
The first and probably irrelevant problem is that the email is not valid the gpx.xsd does not allow - in the domain name. It is hard to fix and can probably be ignored.
The other problem that is relevant and likely the source of the problem with c:geo from the post below is that some tags are incorrect
pgc generates for example
and the correct GSAK one is
The same proble on
Another error is
The forth and last tag that pgc creates
<gsak:FavPoints>0</gsak:FavPoints> is correct