That would be odd. The skip button skips the next route point in its list, whether it is a via point or a shaping point.
If you find the Edit Route option, (3 dot menu on the map display) there are two options in there.
1 Skip the next Via Point - and it names it
2 Skip the next Shaping Point - and it names that.
Unfortunately it doesn't tell you which comes first - and since the XT assigns its own names to many of its route points, you may not recognise the name that it displays.
It is probably best to think if your route as the trip list. The list of points that the XT has to visit in the correct sequence.
Skip removes either:
- The point that it is currently trying to take you to - ie the one that is now top of its list.
- The next shaping point or the next via point in its list depending which option you selected. One of those will be the one that you are heading towards at the moment, the other will be further down the trip list may much further down the list.
A more detailed explanation is given in the link below, and continues on the following page. I'll investigate the disappearance of the skip button and modify these notes accordingly.
I reported the issues described here a good while ago.
See my follow up post below. I edited my settings a long time ago, which might be why I get to see the Skip button all of the time my trip is running.