Garmin Backcountry Skiing - Sprint Result

I use my Fenix 7 for a variety of sports (trail running, XC skiing - skate and classic, mountain biking and back-country skiing).  When using it for back-country skiing, I often get a "sprint" result despite spending little to no time in zone 4 and 5 (versus running, cycling, XC skiing, where I almost never get a "sprint" result despite spending a significant percentage of the workout in zone 4).  To me back-country skiing feels more like base training and the heart rate distribution seems more like a "base" result.  Can you please explain why I am getting "sprint" almost all the time when back-country skiing?  Here's an example of a back-country ski outing where my result was "sprint". 

Zone 5   > 165 bpm • Maximum  0:00 0%
Zone 4   146 - 164 bpm • Threshold  0:11 0%
Zone 3   128 - 145 bpm • Aerobic   4:02 0%
Zone 2   110 - 127 bpm • Easy  58:53 12%
Zone 1   92 - 109 bpm • Warm Up  3:25:28 43%
Thanks!