Will there be an immediate charge if the subscription of the Xiaomi Home Secure is renewed after cancellation?

If your current device has a Xiaomi Home Secure subscription and you cancel the automatic renewal at a certain point in time, renewing your subscription again in the same month (by renewing your subscription in the subscription list or on the Xiaomi Home Secure purchase page) is simply re-activating your subscription for auto-renew and does not mean that you will be charged at that current time.
If your device's auto-renewal period has expired (more than one natural month from the last charge), the renewal will be charged directly and automatically renewed in the next period.