Maybe I’ve identified a relation to the poly count of the mesh. We have 6 levels with water meshes. 3 of them are incorrect:
Mesh 1: Tris: 8.560 Verts: 4.515 correct
Mesh 2: Tris: 33.872 Verts: 18.272 correct
Mesh 3: Tris: 45.696 Verts: 24.293 correct
Mesh 4: Tris: 25.152 Verts: 23.497 incorrect (with little bit different behavior: the mesh is not damaged with artefacts but it is full white)
Mesh 5: Tris: 41.172 Verts: 42.737 incorrect
Mesh 6: Tris: 101.112 Verts: 157.419 incorrect
I hope this helps.