Niagara Grid 3D Gas broken when moving from 5.5 to 5.6

I have a Niagara VFX tutorial series I did in Unreal 5.5
When I open a copy of the project in 5.6, all of the 3D gas looks like it has peppered noise throughout the volume.

Any ideas what’s causing this? I’ve been enabling, disabling, changing settings trying to locate the cause of it and figured I’d hop on here and see if anyone else knows already.

Here it is in 5.5:

Same project/level opened in 5.6:

It’s like pepper sprinkled throughout the volume.
Any advice much appreciated.

John