fixed ip

[#1]

Suppose if I have a subnet 10.54.140.0/24 created in IPAM and from that subnet one IP 10.54.140.16 is made fixed IP with a MAC address 1c:6a:7a:91:e7:e8. Now that IP is assigned to a device manually(Static) and for that device the MAC address is 087b.872e.c120(Not the one that was used in fixed IP). And there is no DHCP scope for our network 10.54.140.0/24 and on the device DHCP is not enabled.

So will this cause any issue for the device to which the IP 10.54.140.16 is given static or is it correct?

[#2]

Yes, although you used a fixed IP, the DHCP server will still ping the IP address when the client sends a DHCPDISCOVER, and because there is another device using that IP address the DHCP server will receive an ICMP echo reply and mark the address as abandoned, meaning the client with the fixed IP will not get an IP address.