I am cross-posting this from Garmin Swim 2 forum, as there are multiple complaints about the problem where swim actiities recorded by Garmin Swim 2 are corrupted if the new HRM-Pro Plus is used. Corrupted actiity does not upload to Garmin Connect.
Since around 4-5 months Garmin Swim 2, when used together with HRM Pro, for open water or pool swimming, would not upload finished activities to Connect (via BT).
Actiity history on the phone shows the swim and swimming total for the week includes the activity. However it does not appear in Connect when synchronised.
This had been happening sporadically without any error messages - ie. heart rate data is uploaded and activity is saved as per the watch.
I had tried to isolate the bug by turning off the internal hrm, then enabling and connecting internal. Sometime it works sometimes not.
It seems that the swim start has to be given when the HRM band is outside the water AND when activvity finishes, to stop the activity one needs to wait outside the water a bit.