I used to be able to reset player offline when i did /scoreboard players reset @a but now it just stays in the scoreboard.

To recreate this:

1: make a new scoreboard

2: set the scoreboard to display at sidebar

3: have a new player join and add a score to that player

4: have the player leave the world

5: try to reset the score of all players (/scoreboard players reset @a score)

You can add a score to yourself, and when you do the reset, it will reset you, but not the other offline player. This used to work, but it broke recently.