Hi Alexander,
Here are some conversion that succeeded but in QGIS is not same.
Gpx → Osm
Gpx → Gml
Gpx → Gpx
Gpx → Topojson
Attached Input + Output +QGIS files
4524 - Aspose.7z (1.5 MB)
Your quick answer is a…...problems in specifix input Aspose.GIS Product Family danies8 April...file to Gml format … with Aspose.GIS lib. It converted correctly...