Streak gage shield

I've been having a reoccurring bug where the Shield from sterak won't appear. I'm aware it's only .75second shield. What I'm talking about however if when I take damage from full health. Just walked out of the fountain to defend inhibitor turret and get dived Take 3002 damage in 2.2 seconds And die despite having 3006 hp maximum

The shield isn't triggering despite Sterak going on cool down and Is not blocking damage And it's impossible to test it's functionality alone.

Please run some tests Riot I'm tired of getting 100- zero and knowing my anti Burst item doesn't work which I invest synergy into from stacking health.