Swimming with the 5+ is not throwing up any issues, other than a somewhat 'wobbly track - https://connect.garmin.com/modern/activity/3280496100. The course we usually swim is ~2000m so allowing for tides, and issues with swimming in straight lines, the swim this morning was close enough in distance. There's usually good correlation with my wife's 935 - https://connect.garmin.com/modern/activity/3266975029
However distance alerts, are another issue. On the 5+ I have a distance alert set for every 500m. Usually we swim out to the first buoy and pause, so I press lap. The distance is ~250m. We then swim down the buoy line to the end ~750m. Having pressed the lap button at the first buoy, I now get alerts at 500m (from the start of the swim) and another 500m after the lap button press - so two alerts. My preference is still to have the alert every 500m with reference to the start of the swim, and not have an extra alert thrown in. It's not too bad in this instance as it's ~250m before the first lap press. But with a shorter distance to a lap press, it is possible to end up with two distance alerts in close proximity.
Either have the alert distance reset at lap button press, or ignore the lap button press and allow the alert to trigger at 500m intervals from the start as set up please.
Of course others might disagree, and be happy with having two distance alerts...