The bug
If a scoreboard objective is set to display in the player list, players without scores appear as having a score of 0.
How to reproduce
Create a new world
Run
/scoreboard objectives add test dummy
Run
/scoreboard objectives setdisplay list test
→ ❌ Notice that, while the player has no score recorded, they appear as having a score of 0 in the player list
Example
Here is an example in video:
[media]Linked issues
is duplicated by 1
relates to 1
Attachments
Comments 10

Can't reproduce
Can confirm now, thank you. As shown it can also erroneously put a 0 on the sidebar, though the player still has no score (@a[scores={test=0}] finds no one)
yes, if u add the score to list it will show 0, then if u add it to sidebar it will show 0 while still have no value until it get one and get reset again
yes, if u add the score to list it will show 0, then if u add it to sidebar it will show 0 while still have no value until it get one and get reset again