Custom Depth and DOF Issue

I have a scene all rendered out and composited in after effects. I utilized a Custom Depth pass to separate the BG with a Luma Matte so I could incorporate my own background (Since you cannot export out transparent image sequences). It all looks great! However, the shot heavily utilizes Depth of Field. The only issue is that I noticed the Custom Depth has no option to allow depth of field. This causes an artifact where I have this really sharp line on the edge of my luma matte. Which is a part of the image that is heavily out of focus.

Is there any way I can allow the custom depth to render out with Depth of Field? Or if there is a option im missing or a workaround where I can make it work? This would be a great feature to have.

Anyone have a solution or an idea of what I can do to solve this?