Strata building insurance usually covers lot fixtures and fittings as well as common property. Sometimes this is more than what is legally required but none-the-less some lot property is usually covered. And the lot owner can claim where it is covered.
Strata building insurance does not cover lot contents.
That a screw failed in a lot fixture would not be an insurable event. It’s a defect or a failure. There would be likely no negligence for such an incident and therefore likely no liable party. So repairing the cupboard itself would be a lot responsibility.
But the consequential damage from the failure might be covered by strata building insurance where it damaged common property or other lot fixtures and fittings. Else other damaged lot contents might be claimable on the lot’s contents insurance (if the lot has any).