When re-entering the game, all existing scoreboards are removed

Put the summary of the bug you're having here
1. join the world
2. create new scoreboard
3. quit this world
4. rejoin this world
5. Typing in /scoreboard objectives list found that all scoreboards be clear
What I expected to happen was...:
Describe what you thought should happen here
Exiting the world should not affect the scoreboard
What actually happened was...:
scoreboard be clear

Steps to Reproduce:
1. join the world
2. create new scoreboard
3. quit this world
4. rejoin this world