Garmin Geek - 920XT Swimming Tip
I also saw many swimmers pressing the "pause" button, bottom right of the screen, at the end of each 100m interval. Confusingly the button is labelled "Enter". If instead you press "lap", bottom left. Labelled "Back" at the start and end of each interval, you will get better data when it loads up to Connect/Strava. It will also help you count your lengths as the screen will show the distance of this lap, rather than your total distance in the session.
If anyone wants me to show them, I'll be at the pool on Friday and Wednesday as usual.