can anyone figure out what's wrong?

i have execute at @s as @s if predicate event:stalking run playsound minecraft:block.amethyst.step where event:stalking is: 
    "condition": "minecraft:entity_properties",
    "entity": "this",
    "predicate": {
      "stepping_on": {
        "block": {
          "blocks": "minecraft:grass_block"
        }
      }
    }
  }

also, the function is running every tick