As with all good answers, it depends.
1) Mineral oil bottle at x location was not labeled: You grab the lead/supervisor of the area and have them go get a label for the bottle. You write it up and consider it corrected. If it happens again the next walk through, then perhaps a RCA/CAPA is necessary because apparently someone does not understand that secondary containers need to be labeled.
2) Pipe insulation behind mixer 2 is falling apart. Write it up and submit a work order to have the insulation replaced.
3) Review of CCP check paperwork revealed several instances of missing or incomplete documentation: Immediately gather the person responsible for the check and their supervisor. Explain the non-conformance and needed correction. Raise a formal NC and do the whole RCA/CAPA thing because it's a CCP and there is no excuse for not following proper procedure. Obviously there is/are things that need to be done to ensure it does not happen again.
Unless you have the time and people available to do a full blown CAPA for every minor thing you may find in a GMP walkthrough, they are generally a waste of time. Pick and choose, based upon risk, of course, those things that need to be formally investigated and action plans created for.
Marshall