Scoreboard not working properly

After execution of complex command chain through function(s) the scoreboard hides from the sidebar and stops to respond to commands like "scoreboard players get @s <Objective>" when there is an assigned value and when there isn't responds in the chat that there is no assigned value to this player/entity. After restart of the world everything is working again and the changes are saved.

EDIT: Works just fine on version 18w02a