TL;DR: There is bug in navigation that softbricks my Fenix 5. I can reproduce it.
Long version:
First time I have observed this issue last year on 50k ultra. At some point I noticed that responsiveness of the watch dropped a lot. It was really laggy and I was suspecting it's the navigation and decided to stop it. But it was too late. The watch was beeping, probably on/off course signal, but the display was not responding. I let at this stuck state for an hour or so. I was hoping that once I clear an 800m climb and get to a plateau area, the navigation will sort itself out (it did not). I tried turning it off and on again, but the watch was stuck on blue triangle. So I hard reset the watch halfway into the race.
Recently, I was re-running activity, about 13k, and I ended up hard resetting the watch after it. It had the exact same degrading development as during the ultra mentioned above. This time I did not do anything about the watch while on the slope and my idea was to let it run out of battery, recharge it and be done with this is. Wrong, very wrong! It got only as far as blue triangle. I did the same track a week before, but that time it was from a gpx export I did on a map. And it was fine, no issues.
Couple weeks ago I noticed that there is a beta 22.40(cad2689) that should have this "Fix potential device crashes and freezes.". Loaded the beta up on to freshly hard reset Fenix 5 and went out to test it. I have loaded the activity (the one that bricked it before) that I recorded and was re-running on previous stable version (whatever it was before 22.40).
Everything else on the watch was on default. I have used "Run" activity, added virtual partner and used HRM TRI. The watch soft bricked itself..again.
I have 3 take-aways from this
- the watch cannot handle jagged/irregular gps while navigating a previous activity
- the number of waypoints/points seems to be the issue as I would expect a watch will record more points than what exported map does
- Fenix 5 has a software bug in navigation that it will literately soft-brick itself
It would be really nice, if you Garmin, could fix this. Or at least make the navigation less destructive. For example, exit the navigation on it's own. It's would be annoying, but lot less annoying than having to hard reset your device.
I am attaching the activity that caused the crash on 2 consecutive re-runs. FIT exported via gpsbabel and trimmed start/end of the log. Around 6th km it becomes obvious that the watch is struggling and by the 8th km, it was bricked.