Buggy IP manual assigment on AC68P [Merlin 380.57_0]

In the web interface, when I try to manually assign an ip address to a mac address, it writes down the configuration, but my device still has the same undesired ip.


I tried to reset three times with:

- Power On + WPS
- Reset
- mtd-erase2 nvram

I assign adresses in: LAN -> DHCP Server

Do you have a solution? I out of idea.