Well it just a requirement when using World Partition, it need that cell grid to do it (so of level streaming) of objects World Partition in Unreal Engine | Unreal Engine 5.5 Documentation | Epic Developer Community
A new method 3d grid(was only 2d before) was added on ue5.4(and made default) so am guessing when people tried to upgrade their project, in someway that setting hash method was set to null and since world partition need that method, it pop out that error.