SELF_REFERENCE_FROM_TRIGGER

A trigger tried to update or delete a record that is already being processed by a trigger in the same transaction.

Common causes

• An after trigger runs DML on the same records it is processing.
• A trigger on object A updates object B, whose trigger updates A again.
• A before delete trigger tries to update the record being deleted.

How to fix

• To change fields on the triggering record, set them in a before trigger with no DML:

trigger AccountTrigger on Account (before update) {
    for (Account a : Trigger.new) {
        a.Description = 'Updated';  // no update statement needed
    }
}

• Break circular updates with a static flag that prevents the second pass.
• Review flows and triggers on both objects together to see the full chain.