Spoils Of War not executing

I have been playing Thresh support for the past 2 days and use Relic Shield as my supporting item. The passive is the Spoils of War, which executes minions below a certain health, gives you and your lane buddy the gold when you AA the minion. My issue is that the execute is not taking place. I can last hit a minion to share the gold and health but I can NOT execute minions. I don't know if it's only happening on my account or on specifically Thresh. I do know that it is happening and it is a little more tricky to lane with Relic Shield. It's the passive itself not working to clarify. It is the same issue with Targon's Brace and Face of the Mountain. I hope if this is a global issue that it will be resolved soon.