Nightwing has been overly stressed after the Invasion. Wally was saved due to the Scarab's warning and everything went back to, relatively, normal. But... Nightwing is scorned by nearly everyone due to the mental strain and severe danger he brought upon everyone. Was he forgiven? By some but not really those that matter to his own mental state. Barbra and Tim still feel betrayed by them... and Wally is still angry with him for putting Artemis's life on the line like that. But with all this stress and guilt... well... not even Nightwing is invincible.