The world is a wacky place and when regimes change, not all of the little rules change at the same time. When I was younger, I wanted to do some travel abroad and for that I needed a passport. I never really thought about what this in depth but this it not only allowing you to leave but in reality it is more permission to let me back into the country in the future.
In Uzbekistan you need the passport to travel within Uzbekistan and before you can leave the country, you need to get special permission in order to leave. This permission is a special form that will last for two years and is put into your passport. This is not directly connected to your passport. If this two year permission is exceeded the passport doesn’t become invalid, nor will this prevent you from entering Uzbekistan. However, when you enter the country with this permission and it expires you cannot leave until you get this permission renewed. Apparently this set of permissions has its roots in the olden days within the Soviet Union.
The good news, or not so good news is that if you are trying to leave Moscow and they see that your permission to leave Uzbekistan has expired they will show enough solidarity with the Uzbek government and will not let you fly to your desired destination but rather they fly back to Uzbekistan.
It is possible to get a more permanent permission to leave, but for that one you will need the permission from both of your parents.