Chris found this error while testing cesm2_3_alpha02d. It is due to an updated CESM FMS external (fi_20210419) which requires an update to the CAM FV3 dycore which uses FMS. The FV3 PR will be submitted soon and will include updates to the FV3 dycore as well as an update to the CAM FMS external bringing it up to fi_20210419. Both MOM and FV3 use the FMS library which can lead to the CESM FMS externals use for MOM being out of sync with the CAM FMS external version. MOM is transitioning away from use of FMS which will prevent future version conflicts.