sysctl.conf - persistent parameter settings ?

I am having problems making my kernel parameters persistent across re-boots.

In my case the parameter "net.ipv4.ip_forward" is set to "1" and I would like it to be set to "0".

Updated the "/etc/sysctl.conf" with the line "net.ipv4.ip_forward = 0".

Ran "sysctl -p".
Confirmed that the "1" had changed to "0".

Re-booted

And "net.ipv4.ip_forward" had been set back to "1".

There are several items I would like to know:
-) Where is the "1" setting coming from ?
-) From research (Googly) it seems to indicate that running "sysctl -p" / "sysctl.conf" is the correct way to go, did I miss something?
-) Does "sysctl -p" store the value elsewhere?

RHEL 7.3 Maipo
Attached are screen prints of my activity.