[GAMEPLAY] Veigar- Ult does 0 damage on Riven

I knew riven (E) giving her shield. But everytime my veigar ult Riven with <5% hp(+ shield). The Veigar ult (R) does 0 damage . Nor reduce riven shield . couple time , R projectile dissapear in mid air if riven dash or jump at spesific time(at veigar cast time or so)