ALTER TABLE ... ADD PARTITION does not work properly on a RANGE COLUMNS partitioned table

ALTER TABLE ... ADD PARTITION does not work properly on a RANGE COLUMNS partitioned table: a task in MiMo-V2.6-RL-harbor-code: MiMo-V2.6-RL Code (Harbor) (Harbor dataset). I have a table partitioned by RANGE COLUMNS (in my case on a date column, but the issue isn't specific to dates), e.g. roughly: