First Home Buyer - Piles without Permit Undisclosed

Hi all, I am currently working through meeting the conditions of an offer that was accepted on a house. Real Estate agent suggested some builders for builders report but I decided to use my own. She called today saying the buyer is a bit worried because there are piles that do not have a permit. Agent did not know apparently. Nothing was disclosed until now. The builder they recommended was the one that did the piles (put on concrete pavers)

This should have been disclosed right at the start if I am correct? As it was in their builders report when they bought the property, so they were aware of it.

I asked my builder to take a good look at them but if they are not consented, I wonder if this voids any insurance? Doing this all by myself so it’s a bit overwhelming. Would love some advice 🥹