Could also be Kucoin selectively enforcing KYC hoping for people to abandon their accounts with funds in them, especially when the funds left in the accounts are not worth walking yourself through KYC for. This usually is the first signal of a more structural change that their platform will be subject to.

I would definitely exercise caution. The last thing you want is to send them a whole Bitcoin and then find out that you can't do anything with your funds until you are verified. Most exchanges don't warn you when your account is empty, the bastards that they are. They just want to make sure they gain something from you first.