Github #19 reports that in order to successfully import a specific file, the user had to suppress a number of elements
It's odd that speed (in particular) needed to be suppressed, as GPXIN-16
was supposed to implement auto-detection.
However, the user's GPX file uses a route (support added in GPX-27) so it may be related to that.
Running a quick test, failure to do so doesn't just generate NOTICE level errors, but also results in a fatal:
Fatal error: Cannot access empty property in /home/ben/Documents/src.old/PHP-GPX-Ingest/src/GPXIngest/GPXIngest.php on line 573