ClientError: An error occurred (EntityTooSmall) when calling CompleteMultipartUpload

Happened while trying to complete a multipart upload in 3 parts of 5MB, 5MB, and 1.3MB. I tried the same operation a second time, and it worked : https://ee.preprod.arkindex.teklia.com/model/94ccf414-9223-47ce-b628-cf381fd28041.

Sentry Issue: ARKINDEX-BACKEND-2TH

ClientError: An error occurred (EntityTooSmall) when calling the CompleteMultipartUpload operation: None
(15 additional frame(s) were not displayed)
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  File "arkindex/upload/api.py", line 118, in create
  File "arkindex/upload/serializers.py", line 215, in create
  File "arkindex/upload/serializers.py", line 37, in handle_s3_client_error
  File "arkindex/upload/serializers.py", line 193, in create