I noticed that the huge increase did not affect Bitcoin fee and I was a bit surprised. It made me wonder whether something big was fixed in the past that I missed.
I wonder what binance did exactly that could increase the transactions to such extent without affecting the fee.
it's easy, they only sent transactions with the minimum fee, but 90MB of them. Because there wasn't much demand for transactions over the weekend, the backlog got cleared up pretty quick.
Additionally, the transactions were
all standard pay-to-public-key-hash, which meant they were not segwit, and blocks with those type of transactions are weighted more heavily, and so drag the possible maximum block size lower. And it didn't really make any difference despite that.