Today at the end of a long run I had a popup on the watch notifying me about the new 1 mile personal record. It turns out there also was 1 km personal record too - see the screenshot from Garmin Connect below. That can't possibly be right because the run was actually very slow and on steep mountainous terrain. The weather was very hot too. I doubt that any of my miles were faster than 10 minutes.
Note that I used All Satellites + Multi Band GNSS mode. The track appears accurate with no obvious glitches that could explain the super fast PR pace. The pace graph below appears accurate too, and nothing on that graph explains the PR numbers above. As I mentioned above, the pace hardly ever goes above 10:00/mile.
The only one thing that was different today is that I experimented with using the Ultra Run mode because I want to use it in upcoming race. I enabled automatic rest timers, which was triggered multiple times, and I used the manual rest timer once too. I wonder if the presence of the rest timer somehow messed up the 1 km and 1 mile PR detection?
Has anyone seen this issue before? How comes that every time I try to use a new feature there is always a bug. There are so many bugs that I wonder if these new features are ever tested by real athletes before they get released? I certainly run into a lot of bugs.