I’m also having HR issues when using strength trainer. There is a noticeable lag where I feel my pulse rate increase as I’m going through my reps, however my Whoop HR only increases after I complete and end the set and am physically at rest, ~15 second lag.
This means that while the exercise/set is active, it’s not showing or using my realtime heart rate for the strength trainer calculations.
Whoop Coach says this is a known limitation with optical HR sensors, but my iwatch manages to track the increase in realtime with no issues?