Venu timer not saving time elapsed correctly

I went for a 3 hour hike yesterday. My Venu showed the small number 2 on the timer, while it was recording the elapsed time, approx 50 mins. When I finished my hike and saved the activity, the time was saved as 1 hour and 28 minutes instead of 2 hours, ~50 minutes. But, the gps recorded the walk accurately on the map. What gives, Garmin?

I am also having issues with the HR tracking. The first 1/2 of my hike was up the mountain, the second was down, apprxo 2000ft elevation gain and decent. On the uphill, my heart rate was Zone 5 high. But, the watch dropped down to Zone 2 for approximately 10 minutes, despite my high heart rate. I took the watch off, cleaned the sensor, made sure it was snug, but still low. So I just carried on. 10 minutes later, it went back up to Zone 5. This happens all the time and I have tried all the trouble shooting tips but nothing fixes this random problem including ensuring software up to date, cleaning sensors, watch fit, and reading through the forum posts (no luck). Any ideas out there, community? Thanks!!