Last weekend when following a course on my Fenix 6X I've noticed a number of issues that I haven't seen before. The course was created in the web version of Garmin Connect and transferred to the watch using Garmin Connect mobile app.
The issues are the following:
1) The course ascent/descent values on the watch are quite different than in Garmin Connect (and the actual ascent/descent)
2) The total elevation profile graph is broken - completely flat
3) Some of individual PacePro climb profiles are very jagged and show up to 10x more ascent than actual
4) The watch kept going off-course repeatedly - probably at least 30 times during the entire 20 mile run. Every time it went off-course the map screen would show my position right on top of the course. It didn't seem like it had any actual reason to go off-course.
Here is screenshot of the course profile in Garmin Connect. The total elevation is reasonably good. The actual ascent was 4600 ft.
Here is what I saw on the watch shortly after starting the course. I think what happened here, in this particular screenshot, is that we started the run from a slightly different spot, so when the watch first joined the course it joined it at the very end of the course, which is a loop. Shortly after that, as we continued on the actual course, the watch corrected and re-joined the course at the beginning, but the profile looked flat like the one below for the reminder of the run.
However if I go to the same course now and look at the course profile, here is what I see:
Either way it is quite wrong. Overall, the profile looks right in the second case, but the total ascent is about 3x larger than actual.
Here is one of the climbs towards the end of the run. The ascent shown here - 1154 ft - is wrong by an order of magnitude. That part of a run was a dirt road that used to be a railroad track, and it gained perhaps 100-150 ft in 2.5 miles, and the actual average grade was about 1%. It was quite smooth elevation wise and didn't have those sharp elevation changes shown on the screenshot below:
Also, as I mentioned above, the issue with the watch constantly losing the course and rejoining it was maddening. Often that happened multiple times in a row. Yes, a lot of this course was on a difficult terrain - forested trails on a steep slow with tall evergreen trees and fairly dense canopy. But there is absolutely no reason for the off-course tolerance being so tight considering this is an outdoor watch which is supposedly designed to be used on trails. And I should add that it also lost the course a couple of times on an open terrain with good sky visibility. And every time it lost the course, the position marker was right on top of the course on the map screen. It is definitely something wrong with the algorithm for following the course, and this time it was 10 times worse than I've ever seen before. And even though the watch was able to recover and re-join the course quickly, at a minimum that constant buzzing was distracting, but also it kept resetting PacePro position every time it lost and re-joined the course.
