The problem is the same as your last post. Your cells are still quadratic hexahedra, and it still has invalid values for all but the 8 values used for linear interpolation. When you applied the Calculator, you created a new object, and the Nonlinear Subdivision Level parameter got reset to 1. Set it back to 0, and you will probably get what you expected.
The reason why the output looks different than before (that is, not all NaNs) is that the default behavior of the Calculator is to replace invalid values (i.e. NaNs) with a specific value (defaulted to 0). So you get interpolations with 0 instead of NaN. If you turn on advanced properties and unselect Replace Invalid Results, you will find you will get the NaNs in the output. (You will also get some warnings from the Calculator filter because it will assume that the NaNs came from a problem with its expression rather than NaNs in the input.