PNG Image Shows Background When Printed: How to Fix Transparency Issues in InDesign

When I put a PNG into my InDesign file, it looks like it has a clear background, but when it is printed it does not have a clear background. Instead it has a square shaded outline around the shape, with like a shade over it, on top of whatever is underneath. e.g. My PNG is sitting in a landscape position half over a red background and half of it over an image. The image itself within the PNG is fine, but out toward the edge of the rectangle shape it is not. When printed, over the red background, the background of the PNG is a lighter shade of red. Where it sits over an image, the background is like a deeper colour saturation. How do I fix this so the background of the PNG is transparent, as it should be? Any help is appreciated very much. It's been driving me crazy

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