Render Layers and an alpha outline

[DartFrog]

I'm not sure render layers are working as intended or if my setup just isn't right. This is in all versions of the octane plugin. I'm in 4.00 XB3 - 6.02 right now. So If I have a white floor and a box in the middle of the shot, and a sphere in front of the box, and they all render on different Render IDs (with normal as the visibility mode), and I render them out as PNGs (16 bit) and load them up in photoshop, I'll get a slight outline where all the items 'touch' in my photoshop file. If I were to put like a bright red fill layer on the bottom of my stack, I'd see the red through the edges of all the layers. What is causing this, and what is the way to fix it? Is it a bug or just some unfixable thing due to the nature of the universe?

[DartFrog]

I attached some JPEGs of what I'm talking about.
I have tried PNG, Tiff, EXR, Targa (which only saves at 8 bit no matter what (??)), in all different bit depths. Some with Pre-multiplied alpha, some without, some with show environment checked, some without. etc.
I think I tried all the possible combinations I can think of for file formats and settings.

My thoughts are that when all the Layer IDs are used and layered up, it shouldn't still show pixels behind it, like it is in Photoshop currently.

[richardyarlett]

My advice is to simple put the FULL RENDERED FRAME, with all three objects, on the bottom of the stack as a background, and then whatever slight antialiases errors are showing through, will disappear with the full image as a background. I know that is not the ideal answer, or the point of it, but it is very hard to get a perfect edge.