DFF errror

I have a plane that when I run verification on gives me errors on the 90 degree corners of every rectangular cutout  on it.

The error is:

"DFF Error:Sliver on Power Inner Layer 3"

I have attached a screen capture of the plane with the errors.

I suspect it has something to do with line width of the hatch but I played with the line width under the planes (selected the

planes shape and went to properties) properties and it did not seem to help.

Any ideas how to clear or fix these errors?

Thank you