DHCP: configuração incorreta endereço fixo?

Question

Minha configuração de DHCP é:

dns-update-style interim;
default-lease-time 86400;
max-lease-time 86400;
authoritative;
log-facility local7;
subnet 192.0.1.0 netmask 255.255.255.0 {
pool {
    option subnet-mask 255.255.255.0;
    option broadcast-address 192.0.1.255;
    option routers 192.0.1.1;
    option domain-name-servers 8.8.8.8, 8.8.4.4;
    range 192.0.1.231 192.0.1.231;
    host host_1 {
        hardware ethernet 5C:DC:96:04:1C:CA;
        fixed-address 192.0.1.231;
    }
    range 192.0.1.230 192.0.1.230;
    host host_2 {
        hardware ethernet 7C:01:91:1D:29:B9;
        fixed-address 192.0.1.230;
    }
    range 192.0.1.229 192.0.1.229;
    host host_3 {
        hardware ethernet 6C:88:14:DD:19:D0;
        fixed-address 192.0.1.229;
    }
    deny unknown-clients;
}
pool {
    option subnet-mask 255.255.255.0;
    option broadcast-address 192.0.1.255;
    option routers 192.0.1.1;
    option domain-name-servers 8.8.8.8, 8.8.4.4;
    range 192.0.1.40 192.0.1.40;
    allow unknown-clients;
}
}

E meu problema é que algumas vezes algum usuário, por exemplo, com MAC "6C: 88: 14: DD: 19: D0" pega o IP 192.0.1.230 quando deve pegar o IP 192.0.1.229 ... qual é o problema?.

Eu tenho essas mensagens no meu sistema de log:

Feb  2 19:35:05 localhost dhcpd: Abandoning IP address 192.0.1.230: declined. 
Feb  2 19:35:05 localhost dhcpd: DHCPDECLINE of 192.0.1.230 from 6C:88:14:DD:19:D0 via enp14s0: abandoned

Mas o usuário 192.0.1.230 sempre tem acesso à internet.