Once upon a time a man was looking for material for the ocean and I suggested
such an variant. In Corona v3 everything was fine (image 1).
Recently installed v5, for the sake of interest visualized the old scene and was surprised by the presence of incomprehensible defects (image 2). Started looking for a reason and it turned out that the problem is in the channel Volumetrics (if understand correctly). If the material is applied to one plane, then everything is fine (image 3), but if to composite (Cloner or Grouping), then something incomprehensible (image 4).
Tried instead Refraction apply Opacity - the same (figure 5, for more dramatic Scattering lighter).