A case of the tail wagging the dog.
The strata manager and the building manager are agents of the owners. The SM and the BM do the work instructed to the by the owners.
The opinion of the BM does not matter, the BM can make a report (he needs to be qualified or get an expert to make that report) to the committee and the committee decides what is done next.
To me its clear that there are some building defects. Its unfortunate that the builder has one broke. It then leaves it up to the OC to effect repairs.
Recent court cases have said that the OC cant just sit on their hands whilst some background processes are happening. The OC needs to effect repairs so that occupants are not inconvenienced
I’d put my complaint in writing to the strata manager explaining exactly the problem, and any remedial actions taken.
Id give the committee two months to act, and then seek mediation at Fair Trading as a precursor to getting an order at NCAT.