Calling two $.getJSON methods with a single Function

Question

I have two $.getJSON methods with in a function in my Javascript file, but the first of the two methods does not seem to return any data on occasions. I can not seem to find a pattern or why this is. The second method always runs though. Does anybody know why this is? Below is my code:-

$(document).ready(function(){

    $(document).on('click', '.read-one-recipe-button', function(){

        var id = $(this).attr('data-id');
        var read_ingredients_html = "";

        $.getJSON("http://localhost:8080/recipe_app/api/recipes/read_ingredients.php?id=" + id, function(data_ingredients){
            read_ingredients_html+="<ul>"; 
                $.each(data_ingredients.records, function(key, val){
                    read_ingredients_html+="<li>"; 
                        read_ingredients_html+=val.Ingredient + " " + val.Quantity + " " + val.Comments; 
                    read_ingredients_html+="</li>"; 
                });
            read_ingredients_html+="</ul>";
        });

        $.getJSON("http://localhost:8080/recipe_app/api/recipes/read_one_recipe.php?id=" + id, function(data_recipe){
            var read_one_recipe_html ="";

            read_one_recipe_html+="<div id='read-recipes' class='btn btn-primary pull-right m-b-15px  read-recipes-button'>";
                read_one_recipe_html+="<span class='glyphicon glyphicon-list'></span> Read Recipes";
            read_one_recipe_html+="</div>";

            read_one_recipe_html+="<table class='table table-bordered table-hover'>";
                read_one_recipe_html+="<tr>";
                    read_one_recipe_html+="<th>Recipe</th>";
                    read_one_recipe_html+="<th>Ingredients</th>";
                    read_one_recipe_html+="<th>Step One</th>";
                    read_one_recipe_html+="<th>Step Two</th>";
                    read_one_recipe_html+="<th>Step Three</th>";
                    read_one_recipe_html+="<th>Step Four</th>";
                read_one_recipe_html+="</tr>";

                read_one_recipe_html+="<tr>";
                    // Recipe Name
                    read_one_recipe_html+="<td class='w-15-pct'>" + data_recipe.recipe_name + "</td>";
                    // Recipe Ingredients
                    read_one_recipe_html+="<td class='w-20-pct'>" + read_ingredients_html + "</td>";
                    // Recipe Step One
                    read_one_recipe_html+="<td class='w-20-pct'>" + data_recipe.instruction_one + "</td>";
                    // Recipe Step Two
                    read_one_recipe_html+="<td class='w-20-pct'>" + data_recipe.instruction_two + "</td>";
                    // Recipe Step Three
                    read_one_recipe_html+="<td class='w-20-pct'>" + data_recipe.instruction_three + "</td>";
                    // Recipe Step Four
                    read_one_recipe_html+="<td class='w-20-pct'>" + data_recipe.instruction_four + "</td>";
                read_one_recipe_html+="</tr>";
            read_one_recipe_html+="</table>";

            $('#page-content').html(read_one_recipe_html);

            changePageTitle("Read Recipe");
        });
    });   

});