If a placed sign contains json text with score values and its chunk is reloaded, the json text disappears. Can be checked with those commands:

/scoreboard objectives add Score dummy
/scoreboard players set Name Score 1
/setblock ~ ~ ~ standing_sign 1 replace {Text2:"{\"score\":{\"name\":\"Name\",\"objective\":\"Score\"}}"}
The sign should display "1" on its second row. Then exit and reload the world. The text should have disappeared.