i'm using the same filter method on 2 different arrays with the same amount of elements but im getting back 2 different values

let initialArtists = [
    { id: 0, name: 'Marta Colvin Andrade' },
    { id: 1, name: 'Lamidi Olonade Fakeye'},
    { id: 2, name: 'Louise Nevelson'},
  ];

  let artist = initialArtists.filter(a => a.id);
  
  console.log(artist);

let users = [
    {id: 1, name: "John"},
    {id: 2, name: "Pete"},
    {id: 3, name: "Mary"}
  ];
  
  let someUsers = users.filter(item => item.id);

  console.log(someUsers);

Using the filter method for both arrays, I'm getting unexpected returns for the first artist array .

The first array is returning only 2 elements of the array and the second array is returning all 3.

Your code executes properly, since your first inital artist has id = 0, then it filtered out since filter includes only truthy filter values, so only the rest 2 artists are in the filtered array. It's not clear why you filter it.
Maybe you wanted to get list of user IDs? In that case you need Array::map():

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let initialArtists = [
    { id: 0, name: 'Marta Colvin Andrade' },
    { id: 1, name: 'Lamidi Olonade Fakeye'},
    { id: 2, name: 'Louise Nevelson'},
  ];

  let artist = initialArtists.map(a => a.id);
  
  console.log(artist);

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