QP029 - actually, the basis for verifying the corrective action is the reported non-conformity itself! As you can tell, from the 2 you were written by your CB auditor, if it's not clear what the issue is, then the verification can be open to such foolish findings or worse!
As you will find, scanning posts here, rarely - if ever - do auditors report the 'effectiveness' of the process which is affected by the NC. Your auditor has fallen into this trap. They prey on the fact that you don't know enough about what they've written to push back - force them - into reporting what the real problem is!
So, yes, you may well have some improving to do, with the way your internal audits are done/reported, but your CB could well do with leading by example!
I'd ask them for clarification, before doing anything...