Found this (Filezilla Free)
- Create new bucket
- Upload a file
- Cancel upload some time while uploading
- Observe filename appears in remote bucket
- Exit remote bucket
- Return into remote bucket
- Observe, Result: Bucket appears as empty
- Exit bucket
- Try to delete bucket.
Reproducible result (tried 2 times so far) : Bucket cannot be deleted. Error message: Failed to remove bucket, bucket not empty