Flint AX-1800 - allowed MACs

Hi again.

I tried to set allowed access to Wireguard Server only to some devices with a specific MAC.
I set it in Luci in the section Firewall - Traffic Rules - wgserver_allow. But despite this, I can also access from a mobile whose MAC is not in the whitelist.
Where can I have a mistake?
Thanks

Wireguard is virtual protocol so the source mac address may not work.