Ephemeral Effect - Target Predicate Not Working

[7H3LaughingMan]

I am trying to setup an Ephemeral Effect on a weapon where if you are targeting an ally then the ally is off-guard to the attack. However, from what I can tell the predicate is not working. If I add this to a weapon and target an ally it doesn't apply the -2 to their AC for the attack, but if I remove the predicate it works for all attacks.

{
  "key": "EphemeralEffect",
  "predicate": [
    "target:ally"
  ],
  "selectors": [
    "{item|id}-attack"
  ],
  "uuid": "Compendium.pf2e.conditionitems.Item.AJh5ex99aV6VTggg"
}