I am assuming here that the black lines on the diagram represent blocking terrain. In that case, the diagram is correct. For both squares in question, there is simply no line of effect to the square. Touching a corner or side of the square is not sufficient to give line of effect: "Line of Effect: A clear line from one point to another point in an encounter that doesn't pass through or touch blocking terrain. Unless noted otherwise, there must be line of effect between the origin square of an effect and its intended target for that target to be affected."

The confusion might be caused by this statement in the rules for Cover: "A line isn't blocked if it runs along the edge of an obstacle's or an enemy's square." It's best to bring this line into consideration only if you otherwise have line of effect to the square in question. For example, this clarification applies to the square to the left of the bottom square you were asking about. The blocking terrain near the bottom does not block the two corners in question because you can easily draw line of effect into that square from the origin square.