[GAMEPLAY] Anvia's passive, rebirth, not triggering on ARAM. (Patch 5.8.15)

In my most recent ARAM match, Anivia's rebirth passive did not trigger once in 8 deaths. My build was Rod of Ages, Archangel's, Luden's, Sorcerer's shoes, needlessly large rod. Opponents were Cho'Gath, Nautilus, Riven, Varus, Taric. All but Varus had the Mark summoner spell.