The problem was that tangent layers (being computed on demand in the batch cache generation) were generated but if MR_DATATYPE_LOOPTRI was not present (in some cases) and the looptri_len was 0, leaving the CDATA layer cleared.
The problem was that tangent layers (being computed on demand in the batch cache generation) were generated but if MR_DATATYPE_LOOPTRI was not present (in some cases) and the looptri_len was 0, leaving the CDATA layer cleared.