Go to the Appearance panel. What is above? When the stroke is below the area it appears. Drag it up above the area.
I have, each time highlighted the rounded square edge with the cursor on
the stroke line. The left corner then says "group" Then if I touch on
"stroke" I get the dialog box with a choice to align center, inside or
outside. The fill is black. When I press anything but align center, the
stroke line disappears. I could send you the image from the exercise.
I too can draw a rectangle; I can create a stroke and it appears exactly as
it is supposed to. But the rectangle for the exercise does not. I may have
something to do with the many layers it has but I can't figure it out. I
wonder if it would help if I sent you the image?
18062 Viking Way NW
Poulsbo, WA 98370