Incomplete upload to Scaleway's S3

### Connector Name

destination-S3

### Connector Version

1.9.7

### What step the error happened?

During the sync

### Relevant information

Trying to use Scaleway's S3 object storage (airbyte / data science&engineering training)

Created a connection from some source to my scw bucket.
Airbyte logs a successful sync, with synced records and some kB transferred. Even tried this with a dummy "Sample Data" source.

Upon completion, no folders or objects are visible in the Scaleway bucket console. However, the Scaleway bucket overview shows "1 object and 1 part". Airbyte AI assistance notes "Sync logs show successful upload: `Uploading part FormattedPart(part=Part(key='/commits/2026_05_18_1779108280062_0.csv', size=866809, index=1, isFinal=true)` and `Loaded part 1 (isFinal=true) completes /commits/2026_05_18_1779108280062_0.csv, finishing`"

I could manually upload files to the same bucket and they appear instantly.

Didn't have time/opportunity to check bucket's answers to CLI/API requests, but console UI is already a trouble anyway.

### Relevant log output

```shell

```

### Contribute

- [ ] Yes, I want to contribute

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**Internal Tracking:** https://github.com/airbytehq/oncall/issues/12645

Start with the destination-S3 connector and reproduce the sync against a Scaleway S3 bucket, using the reported upload-part logs as the initial clue. Check the bucket through an API or CLI as well as the console, then compare the completed multipart upload with the visible objects; done means synced files are listed and downloadable in Scaleway.

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