Answer
No — Oracle doesn't guarantee firing order between triggers of the same type on the same table, and IFS Events don't implement Oracle's newer trigger FOLLOWS/PRECEDES ordering clause, so relying on History Log being fully, synchronously written before your own 'after' Custom Event runs isn't a safe assumption, even if it appears to work reliably in testing. A more robust pattern is to skip copying History Log data into a separate custom field or note entirely, and instead query History Log directly, read-only, whenever the audit trail needs to be displayed — for example via an Information Card with a Select-type implementation that joins the history log table and its attribute-detail table, filtered to the specific LU/record keys and a recent time window, and aggregates the matching rows into one readable multi-line summary. This avoids the ordering risk altogether, and if history-table growth/cleanup performance is a concern separately, adding an index on the history table's (table_name, time_stamp) columns measurably speeds up the cleanup job with only a small write-side cost.