If the skill is bound to a mouse button, then the GUI is eating the input actions. That would be the issue the Gui Overlap section covers in the ExampleRoutine Guide.
If your skill is bound to a key, then it's most likely trying to use the skill at a location where the client won't let it. In that case, the mover will fall back to normal movement, and should still continue on. There's no real fix for that, other than making more logic to try and find a better point to Leap Slam to. You can try to adjust the range at which Leap Slam is performed by changing the 60 to something a lot lower.
Under really specific scenarios, it's possible for the bot to get stuck with normal movement, due to it trying to "move forward" to a point, but that point is close to a wall, so the generated point appears on the other side. This can be seen if you run Twilight Strand a bunch and get unlucky with the wooden walls that appear randomly in the middle. I was testing some code recently to try and avoid that, but it's a rather tricky issue to solve without affecting general movement negatively. For now, that specific issue is just a random stuck issue that happens occasional with the bot.