Batch/Scheduled Smart Campaign fails to deliver to qualified leads despite valid asset and qualification settings

We are experiencing an issue where a batch/scheduled Smart Campaign is failing to deliver emails to target leads, even though the exact same email asset delivers successfully when triggered by a live action (e.g., Form Fill).

Technical Details & Findings:

1. Campaign Configuration: The Smart Campaign is a Batch mode campaign. The qualification rules are set to "Each person can run through the flow every time" and Communication Limits are set to "Ignore limit".
2. Asset Validation: The email asset is fully approved. Delivery works perfectly via trigger workflows, confirming the email asset and recipient mail servers are functioning correctly.
3. The Issue: When triggering via "Run Once" or scheduling the batch, the campaign executes but does not deliver to the intended test leads. The Smart List Status currently shows it is only affecting a small subset of people (e.g., around 5 existing people), and our target test leads are being skipped or excluded from the batch run.

I need support to analyze why the batch processing engine/Smart List cache is filtering out our target leads during the batch run, whereas they qualify seamlessly under live trigger conditions. Please help us identify the conflicting filter logic or database sync latency causing this exclusion.