fenix 6 Pro seems WHR is low during the drill mode and is high after the drill mode.
Though my HR should be high during kick in the drill mode, WHR is low.
After kick in the drill mode, though my HR should be down during pull, WHR is steeply high.
Is your WHR in the swim drill mode correct?
Firmware: 4.30 (APAC)
Sensor Hub: 2.60