Please help me to identify whether there is a non conformance or insufficient against ISO 9001:2015 standards.

2. When auditing in Process Line 3 in a clothing manufacture, the auditor notices that a metal detector is located above the conveyor belt just before the clothing is packed for despatch to customers. This is to prevent staples, needles or any other metallic item being packed with the clothes. The auditor asks how this device is calibrated and is told that a test piece is put through on the conveyor each morning before production starts. A check of the current production record appears to confirm this since the box titled MD check is signed and marked with today's date. The Production Manager confirms that the signature belongs to the production supervisor. The auditor asks to see the test piece used to calibrate the device and is shown the top of a tin can. The top is about 100mm in diameter and marked MD Test item 4. The Production Manager confirms that the detector had not found any metal contaminants as far as he knew. Statement: Evidence: Requirement