Garmin malfunction: I walked 15+ miles 2 days ago. App recorded min/mile, duration HR correctly, but says 5.5 miles total

Post a link to the activity.

connect.garmin.com/.../15595409639

Activity is private. You need to change the visibility to public. 

ooops! done. thanks

The times look a bit odd. Where you out walking for almost 10 hours? Moving time is 3 h 15 minutes. So, you must have been standing still or moving really slowly a lot of time.

One thing that cause odd logging is the auto pause. Especially for slower activities like walking and hiking. Don't ever keep it on. It will just give you odd results. But with that said. It should also stop the timer.

We took several breaks along the way to talk to people. It has the speed per mile accurate, but then, it doesn't add up correctly. We took 10 hours for 15 miles, but there was certainly more than 3:15 moving time. We had a pace of about 30 min/mile.There was also no map with it.

Check auto pause and make sure it is disabled. If it is on it can explain some of the issues.

The missing map is odd. Did you see that it connected to GPS? 

Some users experience GPS issues (like missing maps) and they are usually resolved by a restart of the watch.