I just tried it out today on a hike. Yesterday I downloaded and installed the new MapMyRun app for the Gear S3 as just released by Under Armour. Today I went on a hike in the mountains for 3 hours or so and decided to try out MapMy Run. I set it for hiking mode, started it up, and for first couple of hours it was working great. It looked really good (nice clear sharp display with lots of information) and I was well pleased with it, until it just stopped tracking after around 2 hours 20 mins. The display just stopped at the same time and distance travelled etc and stopped updating.
I tried pressing the Back button and the voice announcement offered to Pause tracking. As I did NOT want to pause tracking I clicked the Back button again, and it said it had resumed, but it stuck at same time and distance for the rest of my hike. HOWEVER, it's important that I point out that this apparent bug is not unique to MapMyRun. For past 2-3 weeks I've been suffering similar problem when using SHealth to track my hikes on the S3. It worked great all the time when I first got my S3, but on recent hikes it started auto-pausing itself part way through a hike (as it should do when you stop moving) but would not auto-resume. So it seems that my problem with SHealth is somehow affecting ALL exercise tracking on my S3. It appears that at some point it just auto-pauses itself and will not resume again. This is very frustrating as tracking my hikes and other workouts was one of the main reasons why I bought this smartwatch, but it is now just totally unreliable for this. Soooo frustrating!
If anyone can suggest any fixes I should try I'd really appreciate it.