Clarification on Dataset Lookup Node Behavior with Duplicate Lookup Keys in AJO

Hello ALL,

I have a question regarding the new Dataset Lookup node in Adobe Journey Optimizer (AJO).

Scenario

I have configured a Dataset Lookup using the following lookup key:

Lookup Key: 123

Sample dataset:

Question

How does the Dataset Lookup node behave when there are multiple records matching the same lookup key?

Specifically:

• Does AJO return the first matching record, last matching record, most recent record based on timestamp, or is the behavior non-deterministic?
• Is there any documented logic or prioritization used when duplicate lookup key values exist in the dataset?
• Are duplicate lookup keys supported, or is the lookup key expected to be unique within the dataset?

Observation

In my test, when the lookup key 123 matches multiple records, the journey consistently evaluates to the "Others" condition rather than the expected paths.

I would like to understand:

1. Whether this is the expected behavior when duplicate records exist for the lookup key.
2. If there are any best practices or requirements to enforce uniqueness on the lookup field.
3. Whether there is official documentation describing how Dataset Lookup handles duplicate matches.

Any clarification would be appreciated.

Thank you