Changing Shadow Quality causes SingleLayerWater Materials to disappear

Regression: Tested in UE5/Release-5.0, issue is reproduceable.

This issue appears to be related to the Opacity Mask of the material, as not having an Opacity Mask does not cause the material to disappear at lower Shadow Quality settings.

1. Create a new material
2. Click on the result node of the material and change the Shading Model to SingleLayerWater
3. Set the Blend mode to Masked
4. Create a constant and set its value to 0
5. Plug the constant in to Base Color and Opacity
6. Create a constant and set its value to 1
7. Plug the constant in to Refraction
8. Create a Single Layer Water Material Node
9. Create a Constant Vector 3 node and set it to 1,0,0
10. Create a constant and set its value to 1
11. Multiply the constant and Vector 3
12. Divide the result by 100
13. Plug the divide node in to the Scattering Coefficients of the Single Layer Water Material
14. Create a DistanceToNearestSurface node and divide that by 10
15. Plug the divide node in to the Opacity Mask of the result node of the material
16. Under Scalability Settings, change the Shadow Quality to low

Actual Result: Preview for the material disappears, unplugging the Opacity Mask or raising the Shadow Quality to medium causes the material to reappear.

Expected Result: Material does not disappear when Shadow Quality is reduced.