Hunter's Challenge warm-up and cool-down

I started the Hunter’s Challenge this week and am having issues with the warm-up and cool-down.  Seems to be the same issue for the workouts I rode this week, W1-D3, W1-D4, W1-D6.

I have a Magnus Smart Trainer in ERG mode.  When I start the workout I am supposed to warm-up from the low wattage to the high, however the trainer will lock-in at the ending (highest) wattage from the start.  For example if I am going from 85 to 161 after 10 minutes, I start at 161 at the beginning of the ride.

Same at the end of the ride.  The trainer stays 

I can get around this by turning off ERG mode, but it seems like the wattage should step at the beginning and end of a ride.

I had a similar issue.  Turns out the Ant was dropping out. Not sure if this is what your are experiencing. I’d get a low wattage warm up but then end up in watts at the 170-190 range and I’m only 105 libs!  

Good idea as I was having lots of ant+ drops/searches but I switched to a Mac and Bluetooth when I started Hunter’s Challenge.  My Garmin cadence sensor is still ant+, with very few drops now, but trainer and heart rate monitor are Bluetooth.