As this was a stage 1 audit no nonconformance can be written, in fact the auditor did what he was supposed to do
From the rules:
6 5 2 Stage 1 activities
The stage 1 shall be performed:
C) to evaluate the clients status and understanding regarding requirements of the standard, in particular with respect to the identification of key performance or significant aspects, processes objectives, and operation of the management system;
The auditor identified that the core tools and requirements of the standard were not understood properly.
7.1.5.1.1 Measurement systems analysis
Statistical studies shall be conducted to analyse the variation present in the results of each type of inspection, measurement, and test equipment system identified in the control plan. The analytical methods and acceptance criteria used shall conform to those in reference manuals on measurement systems analysis. Other analytical methods and acceptance criteria may be used if approved by the customer.
Furthermore from the rules
6 5 3 Stage 1 decision
The stage 1 written report shall contain the following information:
b} any areas of concern that could be classified as a major or minor nonconformity at the stage 2 audit;
and
c} the audit team's decision {e.g-, “ready” to proceed or “not ready” to proceed}-
Nonconformities shall not be issued in the stage 1 readiness review report-