Issue: speed tag is m/s

[RsH]

The GPX file starts with the following, and you can identify their software from the gpx creator line... where they specifically name themselves.
<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<gpx creator="Mobile Action http://www.mobileaction.com/" version="1.0" xmlns="http://www.topografix.com/GPX/1/0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.topografix.com/GPX/1/0 http://www.topografix.com/GPX/1/0/gpx.xsd">

I have deactivated the m/s to Km/h conversion when the creator is "Mobile Action http://www.mobileaction.com/" in the latest prerelease 1.29.6. Does it work for you?

No, just tested and am still getting impossible speeds...