My Garmin HRM-Pro Plus chest strap does record HR during swimming, which downloads to the watch when I save the activity after exiting the water, and is included in my Garmin Connect activity uploaded from the watch. My Xert activity synched from Garmin Connect includes the HR data and Xss for open water swims, but does not include it for pool swims.
Is that a bug, or do I need to tweak something to make it work as I expect it to?