Leading zeros in IPv4 address causes system assign different IP

Issue

• Leading zeros in IPv4 address causes system assign different IP.
• When setting the IPADDR in ifcfg file, adding 0 to the front of the last octet of the IP address by mistake, then if restart the network system will assign a different IP, why?

# egrep 'IPADDR|PREFIX' /etc/sysconfig/network-scripts/ifcfg-eth0 
IPADDR=xxx.xxx.xxx.066
PREFIX=24

# service network restart

# ip a | grep eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    inet xxx.xxx.xxx.54/24 brd xxx.xxx.xxx.255 scope global eth0