linux – sysctl -p + return error about disable_ipv6

when performing the sysctl -p on our rhel server

we are getting the following

sysctl -p

sysctl: cannot stat /proc/sys/net/ipv6/conf/eth0/disable_ipv6: No such file or directory

file /proc/sys/net/ipv6/conf/eth0/disable_ipv6

not exists but this isn’t the problem , because on other good machine file also not exist

any advice why sysctl -p return this error ?