The moon_phase filter for entities ignores the value you set and acts as if you set it zero.

As in, { "test": "moon_phase", "operator": "==", "value": 3 } will return true under a full moon instead of a new moon. So will other numbers for the value. Using the "!=" operator will always return false under a full moon.

I have not tested what happens for operators other than "==" or "!=", or for values outside of the 0-7 range.

Edit: Note, I originally thought that the filter just always return true regardless of the phase of the moon, but it actually just returns true under the full moon specifically.

Steps to Reproduce:

1. Download and import the attached behavior pack.
2. This behavior pack adds an environment sensor that has individual triggers for each moon phase to the cow entity. These each trigger unique events that run a say command associated with it.
3. Create a world using the behavior pack. Since the events run commands, the experimental "Holiday Creator Features" toggle needs to be enabled. Preferably disable mob spawning so that you can test with one cow.
4. Set the time to 18000 so that the full moon is clearly visible. (/time set 18000)
5. Spawn a cow.
6. Check what the cow says at that time.
7. Repeatedly add 24000 to the time to skip to the next moon phases, and check what the cow says at each time. (/time add 24000)

Expected Results:

The cow exclusively says that the moon phase is 0 every tick for the full moon, 1 for the waning gibbous, etc.

Observed Results:

The cow says that the moon phase is 0, 1, 2, 3, etc. simultaneously every tick for full moons and nothing for other phases.