Why do my particles spawn with different alpha levels?

I’m trying out the mesh shape in the 2018.3.2f1 build’s particle emitter. I’m also emitting a mesh as the particle in the render mode. I’m also using teh Particles/Standard Surface shader. For whichever rendering mode in the shader I choose that supports alpha, the particles that get emitted all start with different alpha levels. Why is this? Is there a way to get them all to use the same alpha levels when they spawn?

It could be affected by soft particle. You may adjust the soft particle value, change shader to Mobile/Particles/ or disable soft particle in quality settings.