House building

During the site visit, I noticed some discrepancies in the steel structure and highlighted them to the builder. Fortunately the floor slab those columns were meant to support had not been cast, making it easier (and cheaper) to rectify. We went to other items of the project after that, and as the meeting was about to conclude, someone said 'lucky you were here today and spotted those discrepancies'.

I didn't agree completely with the comment, so I explained - in the past 6 months when we worked with the builder, he had been diligent and conscientious. He would have spotted the mistakes and rectified then quietly, and we would have been none the wiser. The Building Contract spells out the standards and performance expected, so this rectification is expected and should be carried out. No questions asked.
The second point I made was that there is no time limit for the Architect to highlight mistakes and discrepancies to the builder, so in fact we could have reported the discrepancies after the floor was cast.

But that would not have been in the spirit of the contract, and is bad for the project. The builder should be grateful that we helped to point out defects as they occur, and be grateful for the help. (which I'm very sure he is)