States, Layers, and Triggers - Need Another Set of Eyes Please

Two places I would look:

Be very sure that the continue button changes the state of the rectangle on the base, and not one of the same name on the layer.

Two of the layers have rectangles with visited states that are not filled, which could allow another piece of text to show through, just as you described. You don't use those visited states (at least, not in the sample), so I would get rid of them.

In general, I fill textboxes unless I have a specific, special reason for seeing through them. Your description sounds like seeing through a textbox could be causing the problem. I would fill them, and make them big enough and placed in the right place to block anything below them that might otherwise show through.