That's what you should expect to happen.
I believe this AV receiver design is about 20 years old, and it was typical of many AV receivers of the time. It will save your settings if and only if you keep it in standby. If you disconnect it from a source of electric power, it will revert to the original factory settings when it is powered up again.
Newer AV receivers have built-in ways to save a user's settings for a limited period of time (a few hours), if electric power goes out. But not indefinitely.
For what it's worth, my AV receiver, a Denon AVR-X4500H, consumes 0.1 Watts in standby mode.
