Selectors not working with scores of offline players
If Entity does not have a score in a scoreboard and is used with selector (@a,@p,@r,@e) it will not be successful.
Eg.
testfor @p[score_test=0] does not work if player has not been set to 0 already. or
testfor @a[score_test_min=10] but player has not been set or just logged into the world for first time it does not work