Loader layouts are shown while downloading the game. If you're using a desktop/mobile app, the game is available locally, so it doesn't need to download anything, so the loader layout won't need to sit there showing download progress, so it starts at 100% complete, at which point presumably your events proceed to the next layout.
Construct couldn't skip that layout automatically even if it wanted to. It doesn't know what your events will do next. So it just sets the completion at 100%, and lets your events proceed.