Issue with speeds in https://www.gpsvisualizer.com/

[sheepthief]

I use the old but excellent Trekbuddy phone app for tracking, RouteConverter for editing the GPX files it produces, and https://www.gpsvisualizer.com/ for viewing.

Recently I've found that though the Trekbuddy GPX files are still fine, files that have been through RouteConverter are interpreted by GPS Visualizer as having insane speeds. I'm fairly sure that older versions of RouteConverter were ok.

I notice that within the Trekbuddy files speeds are as follows -

Code:

        <extensions>
          <nmea:course>8.1</nmea:course>
          <nmea:speed>17.4</nmea:speed>
        </extensions>

And RouteConverter changes them to -

Code:

                <extensions>
                    <nmea:course xmlns:nmea="http://trekbuddy.net/2009/01/gpx/nmea" xmlns:gpxtpx="http://www.garmin.com/xmlschemas/TrackPointExtension/v1">8.1</nmea:course>
                    <nmea:speed xmlns:nmea="http://trekbuddy.net/2009/01/gpx/nmea" xmlns:gpxtpx="http://www.garmin.com/xmlschemas/TrackPointExtension/v1">17.4</nmea:speed>
                </extensions>

I suspect that GPS Visualiser is attempting to interpret the URLs within the nmea extensions as speeds. So, is the issue here that RouteConverter is producing invalid XML/GPS data, or is GPS Visualizer incorrectly interpreting the data?

I'm using RouteConverter 2.31.2, and I'll attach an original and a converted GPX file.