White Border Showing up when I apply an effect to an Illustrator Layer

[Goghls]

I just recently bumped up my DPI on this fie to 350 and when I had done this from the original, I got these white borders around specific Layers within my illustrator file. So I thought I'd just retrace them with the pen tool and Recreate the effect. But whenever that happened the second time around, it left me confused. Does anyone know why this is happening in Illustrator? First time I've run into this issue. 

I'm trying to add a color halftone effect to an illustrator layer, And it produces a white border instead of leaving the area around it transparent. 

[Ton Frederiks]

Check Effect > Document Raster Effects Settings if White background and Add ..px around object is selected.