I only see some kind of weird issue with the Netmask at enp3s0.254 but I can tell you for sure that this is not the case in the DHCP Server configuration for that subnet/VLAN so I have no idea where that is coming from...
Also this command doesn't end at some point : Any way to skip this stuff ?!
All IP's are Static here 
pihole-FTL dhcp-discover
Scanning all your interfaces for DHCP servers and IPv6 routers
Timeout: 6 seconds
-
Received 300 bytes from 10.0.0.138 @ enp3s0.10
Offered IP address: 10.0.0.243
Server IP address: N/A
Relay-agent IP address: N/A
BOOTP server: (empty)
BOOTP file: (empty)
DHCP options:
Message type: DHCPOFFER (2)
server-identifier: 10.0.0.138
lease-time: 86400 ( 1d )
netmask: 255.255.255.0
router: 10.0.0.138
dns-server: 10.0.0.139
dns-server: 10.0.0.139
hostname: "mintel"
domain-name: "thuis.lan"
--- end of options --- -
Received 300 bytes from 10.0.254.1* Received 300 bytes from 10.0.254.1 @ enp3s0.254
Offered IP address: 10.0.254.244
Server IP address: N/A
Relay-agent IP address: N/A
BOOTP server: (empty)
BOOTP file: (empty)
DHCP options:
Message type: DHCPOFFER (2)
server-identifier: 10.0.254.1
lease-time: 86400 ( 1d )
Offered IP address: 192.168.1.102
Server IP address: N/A
Relay-agent IP address: N/A
BOOTP server: (empty)
BOOTP file: (empty)
DHCP options:
Message type: DHCPOFFER (2)
netmask: 192.168.1.102
router: 10.0.254.1
dns-server: 10.0.254.2
dns-server: 10.0.254.2
domain-name: "254.lan"
--- end of options ---server-identifier: 192.168.1.1
lease-time: 86400 ( 1d )
netmask: 255.255.255.0
router: 192.168.1.1
dns-server: 192.168.1.2
dns-server: 192.168.1.2
domain-name: "management.thuis.lan"
--- end of options ---