As of the resolution of MC-240393, it is intended for jungles to not generate on plateaus. However, this does not happen consistently with different humidity levels, causing unnecessary microbiomes. As shown in the screenshots below using the seed -7458002248321719613 and going to the coordinates 9 129 119, jungles will still generate at humidity levels of 4 on a plateau, while jungles on non-plateau terrain have consistent generation between humidity levels of 3 and 4.