Exported gpx files are noisy and non-standard
Locus seems to write horrible gpx files lately... they look more or less like
I suggest stripping the precisions to something reasonable. 9 decimals for lat/lon is major overkill (use 5 or 6 max or at least strip trailing "000" rubbish at the ending of each number). Any decimals at all for elevation, course and pdop are probably nonsense. You could reduce the output size maybe by 50% without losing anything.
Also, the gpxtpx extensions are not included in the schema header, which makes the locus files fail in xml display tools (when you e.g. try to load one into chrome).