I am not surprised to hear this, because some other people have seen it that exchanges goes as far as borrowing funds borrow funds before audit and return the funds after audit to deceive people that they have enough prove of reserve.

Binance last audit was not accepted by people because they said there is no transparency in their PoR. If Binance the biggest exchange can do this then other smaller exchanges will learn and copy from them.
https://www.ccn.com/news/binance-proof-of-reserves-transparency-not-enough/#:~:text=In%20the%20latest%20snapshot%20%2C%20Binance,users%20hold%20in%20their%20accounts