Outer Glow Not Overlapping

Hi all,

I'm having a problem with my outer glow effect not overlapping and creating harsh cutoff lines. I made a blank layer with simple brushstrokes, then applied the outer glow effect, expecting the glow to overlap, but instead, the glow cuts off before it reaches another brush stroke. Is there a way to correct this? I've tried changing the blending mode and the outer glow parameters, but nothing has worked. I know I can make individual shapes with an outer glow effect that will overlap. However, I'm trying to avoid doing that since the document size is already pretty large. Here is a snip of my problem and my layer structure.