I think you need to check, step1 template style -> page selection, footer or footer background, and header or header background, remove the pictures. (image file)

Note ! In case you remove a wrong one, use right mouse button and locate the picture. Or /and make a copy of your template. (open project goto step1 template , use custom template, use add button)

A big thanks to Andre, you made me close my eyes, and the problem is now solved.
See attached file what should be removed (red)

with best regards

Tage Rheimer

Glad to get you on the right track, it's difficult to guess where it exactly is....anyway you sorted it out great !