I am using Rive to trigger Healing Hands, and have two points allocated in Synthesis of Light. I have +155% healing effectiveness.
According to the formula in the tooltip, I should generate 2 ward (1 per point of Synthesis of Light) per +10% healing effectiveness, or 31 ward per attack. Even if the -65% modifier applied to Synthesis of Light, that should still result in 10.5 ward per attack. I am generating 3 ward per attack. I believe that this was a problem in the previous cycle as well.
ETA: I have tried using Healing Hands directly, and I also get 3 ward per attack using my current stats.