I think that what you are talking about is using multiple shared nodes with an unspecified number of tasks on each node. CESM2 does not support that mode of operation. It seems like from your posts that you are adjusting NTASKS but not ROOTPE - so If the original ROOTPE_OCN=98 then the first OCN task is task 98 of COMM_WORLD and so even if all components use only 1 task you've configured the model to use 98.
