When importing large files we can observe these error messages:
Instance has been created in mod-inventory and DI_COMPLETE event sent, after this duplicated event to create instance can be send again to mod-inventory and mod-inventory sends DI_ERROR event with error message that instance already exists to SRM. This DI_ERROR event already has different event id and duplicated record inserted in SRM journal_records table.
To prevent this needed to not not send DI_ERROR from mod-inventory in case when entity already created in inventory-storage.
Notes for devs:
To reproduce it source code in mod-inventory can be modified with invoking CreateInstance/CreateHolding/CreateItem handler twice for testing purposes. Also this can be considered as a scenario for an integration test.