You are auditing an electronic component manufacturer. They have a process for dealing with customer complaints that require them to investigate and take corrective action.
Documented information (records) show that several customers have recently complained about faulty components being delivered. The customers returned the faulty components to the organisation. The organisation then repaired them and returned them back to their customers.
Documented information (records) show that an investigation report found the cause to be that two new employees were undergoing training and had been assigned to tasks where they should have been supervised. Due to staff shortages however, no supervision was provided.

Following the investigation, records show their training had been completed and the employees were assessed as being competent.
There was no evidence of any further investigation or corrective action being carried out and the report had been closed.

Identifying if it  is nonconformity or no nonconformity

1-For correctly identifying the scenario as a nonconformity

2-Description of the nonconformity

3-Relevant evidence

4-SO 9001:2015 clause and requirement