The formula doesn't actually change. Rather, the formula cannot be
resolved when you replace one of your cells with another, hence the
#REF! notations where you expect cells. You have to keep from moving
the cells in column D from one place to another. As I wrote before, if
you want to copy text from one cell in the range to another by dragging
and dropping, hold down the Control key as you move the cell; this
creates a copy of the contents. Otherwise, Copy from the source cell
and Paste into the target cell.

Note again that when you move, say, D1 to D3, the formula in E1 then
refers to D3 instead of D1. So D1 could be blank but E1 could read
"Go" or "No Go" depending on the contents of D3. (And of course, E3
will show #REF! because the cell its formula referred to was replaced.)

If you move a cell in column D and see a #REF! error, Undo immediately
to restore column D to its previous state. This will restore the
references and eliminate the error. Then copy as described above.