3
Just in case anyone else runs into this, here's the solution:
When your setting up the array:
$item_list = array('1' => 'Category 1', '2' => 'Category 2', '3' => 'Category 3');
You MUST use numbers for the item name. I was replacing '1' with 'wuytest'. The database has this field configured as a integer, that's why it won't update plus it also won't work.
Don't you just hate it when you finally realize how obvious your mistake was?