I see what the problem is. The main issue here is that, even though you're overlaying the "stripes" on top of the imagine-canvas items, you're not making a real connection between the stripes and the canvas.
Here's how I'd go about this: I'd create a container class, let's say it's called: parallax-section. Inside the parallax-section I'd place the imagine-canvas together with the stripe overlaying the current section. Next, the sections need to be independent and not overlay each other, therefore I'd use the following CSS for them:
The secret here is, the parallax-section should be taking the width and height of the imagine canvas. The stripes should have an absolute position, with a
z-index: 1 property.
I hope this helps. I can give you the working solution if you want to send me your source code.