Particle Fluid Sim Issues Double Density Relaxation

Hello! I’ve been building out a fluid sim following the Double Density Relaxation method. I am building it in Unreal with Niagara and sim stages. Mostly with HLSL in scratch pad. It’s basically 80% there but I am struggling with this really frustrating issue that has been playing me for weeks. The particles won’t stack beyond a certain point. I am using neighbor grid for the spatial hash system, and they will go up one or two grid cells, but then overlap on themselves until the pressure builds up and then they shoot up to two cells above the current top cell. I have been all over this paper and rebuilt tons of aspects of it, but I’m sure the solution is something I’ve missed or is something weird I’m not catching or understanding. So I’m hoping some of you will have some insight for me. The video shows me adjusting done various settings, and then about 3/4 of the way through the video, that is when I show the issue.

https://youtu.be/ISDHNQccenM