How in the world does the input predicate work

Trying to get the new input predicate working, running the latest snapshot this is my predicate: json { "condition": "minecraft:entity_properties", "entity": "this", "predicate": { "type": "minecraft:player", "input": { "forward": true } } } which is in fact detected by the game, and I'm running this in a repeating command block with: elixir execute if predicate huo.test:forwards run say hi shouldn't this spam hi? whats going on