MM17 Maximum number of fields

Our lawsuit wants to usage Fiori App Mass Maintenance Material to update worldly master.
We usage the functionality "copy from clipboard".
During investigating for MARC array updates wherever astir 30 antithetic fields were to updated for antithetic materials, we discovered immoderate fields astatine the astir close presumption were not updated.  Only the archetypal 18 fields were updated.
As a workaround we are doing 2 successive runs of Fiori App Mass Maintenance Material with little than 18 columns each.
Has anyone encountered aforesaid contented and was capable to resoluteness it?