My watch and app seem to be set everywhere to the metric system, but after completing a run, if I get a record notification based on pace, it displays ‘Fastest mile’ instead of kilometer.
I don't see the problem. I have my watch set at km, and I get personal records in both km and miles. The same happens in Endomondo when not using the watch. I guess if I set my watch at miles, I would still get personal records in both km and miles.
This gives me an option of comparing my personal times with other runners, even though I have my watch set at a different unit. Why is that a problem?