I tested the GPS Recorder app at my Bangle and I got two problems:
I tested tracking my regular Nordic Walking round course, which runs about one hour.
Afterwards, when I download a gpx file from the watch and showed the track in Google Maps, I only saw a part of the walking track: After a few minutes the Bangle started writing coordinates., but after about 40 minutes the track ends abruptly (I double checked with an file editor). This behavior is reproducible.
My second issue is, that kml import to Google Maps is not always working: In the second test run Google Maps produced a vertical line at my meridian instead of the expected track, although in the editor the kml file looked good to me. I then tried gpx format download instead of kml and this worked partly as described above.
Any idea how to fix these?