TL;DR - Edge 840 workouts connected to bike trainer no longer work correctly on software version 26.17 & 26.18.
Over the winter I've been using my edge 840, with workouts created in Garmin Connect app, to control my bike trainer (Elite Direto XR - current fw: 87 rev 7). I prefer this way over zwift or others because I can watch Netflix while riding longer indoor rides and I like getting the Garmin insights after a workout. My last ride on mar 3 was an anaerobic interval ride on version 26.17 - a ride I've done before fine. However, this workout halfway through each interval the resistance just gave up, I'm attaching a screenshot of the planned workout intensity (grey) vs my power (purple line). The whole workout resistance was all over the place.
Puzzled I restarted my trainer, and the edge 840 without remedy. I've since updated the 840 to version 26.18, attempted a different workout ride with the same problem. I'm fairly certain it's not an issue with my trainer because I tried an interval ride on TrainingPeaks Virtual and it was fine - no issues. I'm also experiencing the problem riding on the trainer in free-ride mode manually adjusting resistance on the edge 840.
Anyone experienced this before? Should I try resetting the Edge? If I reset and erase data will I lose my rides and training details/estimates? I'm prepping for a triathlon in mid may so I'd like to avoid loss of data if possible.
Thanks