Well, It's not exactly that. The behavior in the example that I provided works perfectly on sections whose width is equal to or less than 100vw, however when it is greater, as for the "Part Two" section, the snap is triggered from the start of the scroll, preventing the reading of its contents as a whole...
Generally speaking, the snap must be triggered when the right edge of the current section appears on the screen; Here is a screenshot to illustrate all this: