And the problem and solution were
Dear Valued KuCoin User,
Thank you for reaching out to KuCoin customer support.
As you can see on the deposit page, deposit USDT via bep20 chain is unavailable now so that your deposit cannot be credited to your account. We have feedback the issue to the related team and they will credit the token to your account manually. It shall take 1-3 days to check the issue for you. Please wait patiently.
Thank you in advance for your understanding. If you have any other questions or concerns, please feel free to let us know!
Kind regards,
KuCoin Customer Care and Support Team