A senior data engineer executed a `VACUUM orders RETAIN 0 HOURS` command on the `orders` Delta table. During execution, a junior data engineer, unaware of the ongoing task, began ingesting data from a source table with non-zero records into the same `orders` Delta table. Post-ingestion, the junior engineer found the table empty without any error messages, only to later discover that an insert operation was performed in parallel with the vacuum. The table's history showed only `VACUUM` and `INSERT` actions. What could be the reason for this occurrence? | Databricks Certified Data Engineer - Associate Quiz - LeetQuiz