Intensity minutes cycling activity different from intensity minutes calculator in app

Getting similar recording on edge 1050 and HRM pro plus, rides recorded intensity minutes ok. Either when HRM or fenix 7 syncs to connect intensity minutes double ?

I’m getting similar strange results with my intensity minutes. I’m just doing light workouts on a stationary rower and treadmill, walking. Consistently for the past 7 days, the nearly whole workout it being counted as vigorous so doubling my total intense minutes. Looking at the individual workouts it just shows moderate minutes and 0 vigorous which is what I expect. Looking at Intensity Minutes l have most of the time as Vigorous. Posted on Reddit also without any suggestions. My HR and calories are as expected.

I recently upgraded my Garmin watch from the Forerunner 735 to the Fenix 7X Pro. I’ve been doing Zwift training sessions using the Garmin HRM Dual, which syncs with Garmin Connect and calculates other relevant metrics.

Since the upgrade, the intensity minutes aren’t calculating correctly. For example, I’ve been doing threshold and VO₂ intervals, and my heart rate is definitely in Zone 4/ Zone 3 at times, I’ve confirmed this during and after the activity. However, the intensity minutes don’t reflect that.

My primary device for training and as a wearable is the new watch, but I don’t use it during indoor Zwift cycling sessions. I’m also not using the watch to record heart rate; that data comes from the HRM Dual chest strap, which is synced with Zwift during the ride. After the ride, the data syncs to my Garmin account.

This wasn’t an issue with my old watch. Also, I’ve never used the watch—neither before nor now—to record my virtual Zwift workouts.

From what I’ve seen, the activity summary uses one calculation, but the intensity meter also includes non-activity HR data. So if your heart rate stayed elevated after finishing, it can add extra intensity minutes later. Feels confusing but seems normal behavior.