I have been using MEXC for a while now and when I log in it says that I should do a KYC before I do spot or future trading. There is no clear answer to questions in the chat.
But what also surprised me is that Kucoin is specified as the sender for transactions. Could it be that MEXC is a subsidiary of Kucoin and is now also subject to regulation?
Kucoin & MEXC headquartered in Seychelles, so there may have been an update in the legislative regulations of that country.
Do CEXs necessarily require KYC, but the only difference is that some of them are located in countries that are not strict in legislative regulations, so they set limits such as 100 Bitcoins for withdrawal per day and do not require you to deposit in dollars.