Winbox DHCP Server assign IP to static IP device?

Hello All,
My winbox
DHCP Server assign IP to static IP client device.
Why and how to fix it?
or How to filter Mac to unassign IP example: 0A:BB:11 begin?
Thank you.

Nein.

Welcome to the forum, your topic is a bit unclear to me. Nevertheless...:

A DHCP client requests an IP address from the DHCP server.
The address is either selected from a pool (dynamically) or is static.

More information can be found in the documentation:

Adding, it's not Winbox which assigns the DHCP lease.
It's your device. Winbox only acts as interface to be able to interact with your device settings.
What model is your router ?

Static leases are something which have been setup by someone. They do not come on their own.