TIN displayed with contours not matching input point elevations

[NicoleLavoie]

Why am I not able to generate contour lines that match my input points?

I have created a TIN using mass points, which represent elevations (see figure below)

This resulted in the following TIN, symbolized with contours

I have repeated the create TIN process using constrained and unconstrained delaunay, and it does not change the result. Why is it not creating contours that follow the input elevation points? Is there a way to fix this?