[Amazon Seller Partner] GET_V2_SETTLEMENT_REPORT_DATA_FLAT_FILE is empty

### Connector Name

source-amazon-seller-partner

### Connector Version

5.9.0

### What step the error happened?

During the sync

### Relevant information

The GET_V2_SETTLEMENT_REPORT_DATA_FLAT_FILE Stream retrieves 0 rows although there are reports and data available. I was issuing a full sync with start date in the source set to "2026-07-01" (currently 27 days ago). I've checked the same report with a custom script and confirmed existing data in the last 7 days. Why is Airbyte not loading the data?

### Relevant log output

```shell
Sync summary: {
"status" : "completed",
"recordsSynced" : 0,
"bytesSynced" : 0,
"startTime" : 1785136396959,
"endTime" : 1785136425364,
"totalStats" : {
"additionalStats" : { },
"bytesCommitted" : 0,
"bytesEmitted" : 0,
"destinationStateMessagesEmitted" : 2,
"destinationWriteEndTime" : 1785136424672,
"destinationWriteStartTime" : 1785136397660,
"meanSecondsBeforeSourceStateMessageEmitted" : 0,
"maxSecondsBeforeSourceStateMessageEmitted" : 2,
"maxSecondsBetweenStateMessageEmittedandCommitted" : 3,
"meanSecondsBetweenStateMessageEmittedandCommitted" : 3,
"recordsEmitted" : 0,
"recordsCommitted" : 0,
"recordsFilteredOut" : 0,
"bytesFilteredOut" : 0,
"replicationEndTime" : 1785136424677,
"replicationStartTime" : 1785136396959,
"sourceReadEndTime" : 1785136410963,
"sourceReadStartTime" : 1785136397662,
"sourceStateMessagesEmitted" : 2
},
"streamStats" : [ {
"streamName" : "GET_V2_SETTLEMENT_REPORT_DATA_FLAT_FILE",
"stats" : {
"additionalStats" : {
"truncatedValueCount" : 0.0,
"nulledValueCount" : 0.0
},
"bytesCommitted" : 0,
"bytesEmitted" : 0,
"estimatedBytes" : 0,
"estimatedRecords" : 0,
"recordsEmitted" : 0,
"recordsCommitted" : 0,
"recordsFilteredOut" : 0,
"bytesFilteredOut" : 0
}
} ],
"performanceMetrics" : { },
"streamCount" : 1
}
```

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**Internal Tracking:** airbytehq/oncall#13160