Very frustrating. During activities, my Fenix 5 will just freeze. In the background it is still measuring because it announces to my phone distances and pace but I can only see the view on the watch at the moment it freezes. When I complete my activity (e.g. yesterday it froze at 11 miles of a 21 mile run), I can soft reset it and it has only recorded up to the point it froze - all other data beyond that is lost. I have tried the reset suggestions from Garmin (twice now) - and apart from it losing a whole load of data, it also seems to take about 2 hours to re-sync. However this does not seem to be having any improvement.
At the moment I have a very expensive device able to tell the time and have to use my phone / strava for everything else! Come on Garmin, sort it out !!!