I think you just resolved your own issue. The issue is that your mask is moving outside the bounds of what you’re seeing. So it thinks the health bar area is bigger than it really is.
In the video I made the health bar slightly smaller than the length of the canvas which may have caused issues. You can actually apply the scrollbar component to the mask itself as well, just add the script to the mask instead. As long as the mask and the health bar match in size you shouldn’t have any issues. If the object that has the scrollbar is a different size than the mask you’ll have issues.
