locket shield doesnt activate when around kled who just had passive procked

i was playing blitzcrank and had a kled top laner in team fights when kled went low his passive procked i then hit my locket for shield on team but it gave 0 shields to anyone the last time it happened in the game kled was on 100 health i used the ability nothing happened but this time i was out of combat so i would have had a shield until it faded there was no shield which made me sure there wasnt a mistake on my part