You have to be more specific about what the file actually contains. Presumably you are referencing something in AE like a group Null or a mask path for an extrusion and some of that stuff may be broken. Likewise something with your 3D comp settings could have changed and the plug-in fail to update settings.
I Have the same problem. I use After Effects CC 2017 on Windows 10 64bits with a nvidia 970M.
In my composition, I have 4 layers : 1 camera, 1 light, 1 adjustement layer (with "Lumetri color" and "add noise") and a layer with Element 3D.
I try to desactivate my adjustment layer and light, I have the same error. In my mind, it's Element 3D.
In E3D, I use my own UV ( .png file) and on Render Setting, "Lighting", "Ambiant occlusion".
I send a message to VideoCopilot Support too.
Thank guys !
I have found a solution to this. Its the Nvidia driver version.
I had the nVidia 378.66 version installed, which is the most recent release. As soon it was updated I started to get this error. Basically this error popped up when ray trace was on. As soon I switched off ray trace, Element worked fine.
What I did was revert back to driver version 372.90. And YES it worked like a charm. No more leaked effect error.
Try this, it should work.