The original post made it sound like the blade was contacting the mouth plate before protruding. The pictures made it look to me like the mouth plate was too long and causing this. I agree if the plane was purchase new, the best thing would be to return it. I got a little lost by the discussion of adjusting the bedding if the problem is the mouth in front of the plane.
If the sliding mouth plate is of question, and not the blade bedding, the immediate test that comes to mind is to simply remove it, and see if the plane can function without it. If the plane sits on the bed properly, it shouldn't be an issue on stock wide enough.
" Be willing to make mistakes in your basements, garages, apartments and palaces. I have made many. Your first attempts may be poor. They will not be futile. " - M.S. Bickford, Mouldings In Practice