массивы — возникла проблема с сохранением значения нескольких флажков. Переполнение стека

У меня проблемы с сохранением значения для моего массива с несколькими флажками. Загляните на этот сайт и примените ответ к моему, но по какой-то причине не сохраняете проверенное значение. ** вот мой PHP **

       <?php

// start session
session_start();

// i user is not log in redirect back to index
if(!isset($_SESSION['user_type'])){
header('Location: index.php');
}

// include data based connection config
include_once('include/connection.php');

// incluude header ttile page
$title  = "Edit User Profile";

// set user session variables
$userId = $_SESSION['user_id'];
//$userName = $_SESSION['user_name'];
$temp = $_SESSION['user_name'];

//$competency = "";
// if user update the data
if(isset($_POST['update'])){

// define post variable
$firstname = trim($_POST['firstname']);
$lastname = trim($_POST['lastname']);
$email = trim($_POST['email']);
$user_name = trim($_POST['user_name']);
$profession = trim($_POST['profession']);
$phone = trim($_POST['phone']);
$hobbies = trim($_POST['hobbies']);
$skills = trim($_POST['skills']);
$competency = implode(', ', $_POST['competency']);
$postcode = trim($_POST['postcode']);
$address = trim($_POST['address']);
$bio = trim($_POST['bio']);
$dob = trim($_POST['dob']);
$gender = trim($_POST['gender']);
$country = trim($_POST['country']);// ************* UPDATE PROFILE INFORMATION ************************//
if(!($stmt = $con->prepare("UPDATE user SET firstname = ?, lastname = ?, skills = ?, competency = ?, profession = ?,
user_name = ?, phone = ?, address = ?, email = ?, bio = ?,
gender = ?, dob = ?, country = ? WHERE id = ?"))) {
echo "Prepare failed: (" . $con->errno . ")" . $con->error;
}
if(!$stmt->bind_param('ssssssissssssi', $firstname, $lastname, $skills, $competency, $profession,
$user_name, $phone, $address, $email, $bio,
$gender, $dob, $country, $userId)){
echo "Binding paramaters failed:(" . $stmt->errno . ")" . $stmt->error;
}
if(!$stmt->execute()){
echo "Execute failed: (" . $stmt->errno .")" . $stmt->error;
}if($stmt) {
$_SESSION['main_notice'] = "Successfully Updated!";
header('Location: profile.php');
exit;

}else{
$_SESSION['main_notice'] = "Some error, try again";
header('Location: '.$_SERVER['PHP_SELF']);
}

$stmt->close();}

$stmt = $con->prepare("SELECT firstname, lastname, skills, competency, user_name, avatar, profession, email, dob, gender, country, phone, bio, address, created_at FROM user WHERE id = ?");
$stmt->bind_param('s', $userId);
$stmt->execute();
$stmt->store_result();
if($stmt->num_rows == 0) {
echo 'No Data Found for this user';
}else {
$stmt->bind_result($firstname, $lastname, $skills, $competency, $user_name, $avatar, $profession, $email, $dob, $gender, $country, $phone, $bio, $address, $created_at);
$stmt->fetch();

$stmt->close();

}
?>

* А вот и мой HTML *

       <div class="user-details">

<form name="update" action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post" enctype="multipart/form-data" id="UploadForm">

<table>
<label for="">Avatar</label>
<input name="ImageFile" type="file" id="uploadFile"/>
<!--                     <div>
<div class="shortpreview">
<label for="">Previous Avatar </label>
<br>
<img src="userfiles/avatars/<?php //echo $avatar;?>" width='150' height='150' >
</div>
</div> -->
<div class="col-md-6">
<div class="shortpreview" id="uploadImagePreview">
<label for="">Current Uploaded Avatar </label>
<br>
<div id="imagePreview"></div>
</div>
</div>
</table><table>
<tr>
<td></td>
<td></td>
<td>Update</td>
</tr>
<tr>
<td><label for = "">First Name</label></td>
<td><input type="text" id="firstname" name="firstname" value="<?php echo $firstname; ?>"></td>
</tr>

<tr>
<td><label for = "">Last Name</label></td>
<td><input type="text" id="lastname" name="lastname"  value ="<?php echo $lastname; ?>"></td>
</tr>

<tr>
<td><label for = "">Skills</label></td>
<td><input type="text" id="skills" name="skills"  value ="<?php echo $skills; ?>"></td>
</tr>
<tr>
<td>
<label >Competency:</label>
<input type="checkbox" value="RRT" name="competency[]" <?php if(isset($_POST['competency']) && in_array('RRT', $_POST['competency'])) echo 'checked="checked"'; ?>>RRT<br>
<input type="checkbox" value="ESD" name="competency[]" <?php if(isset($_POST['competency']) && in_array('ESD', $_POST['competency'])) echo 'checked="checked"'; ?>>ESD<br>
<input type="checkbox" value="SDT" name="competency[]" <?php if(isset($_POST['competency']) && in_array('SDT', $_POST['competency'])) echo 'checked="checked"'; ?>>SDT<br>
<input type="checkbox" value="CAR" name="competency[]" <?php if(isset($_POST['competency']) && in_array('CAR', $_POST['competency'])) echo 'checked="checked"'; ?>>CAR <br>
<input type="checkbox" value="DH" name="competency[]" <?php if(isset($_POST['competency']) && in_array('DH', $_POST['competency'])) echo 'checked="checked"'; ?>>DH<br>
<input type="checkbox" value="MEDS" name="competency[]" <?php if(isset($_POST['competency']) && in_array('MEDS', $_POST['competency'])) echo 'checked="checked"'; ?>>MEDS <br>

<!--                    <input type="checkbox"  value="RRT" name="competency['RRT']" <?php// if(!empty($_POST['competency']['RRT'])) echo "checked = 'checked'"; ?>>RRT<br>
<input type="checkbox"  value="ESD" name="competency['ESD']" <?php //if(!empty($_POST['competency']['ESD'])) echo "checked = 'checked'"; ?>>ESD<br>
<input type="checkbox"  value="SDT" name="competency['SDT']" <?php //if(!empty($_POST['competency']['SDT'])) echo "checked = 'checked'"; ?>>SDT<br>
<input type="checkbox"  value="CAR" name="competency['CAR']" <?php //if(!empty($_POST['competency']['CAR'])) echo "checked = 'checked'"; ?>>CAR<br>
<input type="checkbox" value="MEDS"  name="competency['MEDS']" <?php// if(!empty($_POST['competency']['MEDS'])) echo "checked = 'checked'"; ?>>MEDS<br>
<input type="checkbox" value="DH"  name="competency['DH']" <?php //if(!empty($_POST['competency']['DH'])) echo "checked = 'checked'"; ?>>DH<br> -->
</td>
</tr>
<!--         <tr>
<td>

<select name="competency[]" multiple="multiple">
<option value="SDT">SDT</option>
<option value="ESD">ESD</option>
<option value="CAR">CAR</option>
<option value="MEDS">MEDS</option>
<option value="DH">DH</option>
</select>

</td>
</tr> -->

<tr>
<td><label for = "">User Nmae</label></td>
<td><input type="text" id="user_name" name="user_name" value="<?php echo $user_name; ?>"></td>
</tr>

<tr>
<td><label for = "">Profession Name</label></td>
<td><input type="text" id="profession" name="profession" value="<?php echo $profession; ?>"></td>
</tr>

<tr>
<td><label for = "">Phone</label></td>
<td><input type="text" id="phone" name="phone" value="<?php echo $phone; ?>"></td>
</tr>

<tr>
<td><label for = "">Email</label></td>
<td><input type="text" id="email" name="email" value="<?php echo $email; ?>"></td>
</tr>

<tr>
<td><label for = "">Gender</label></td>
<td><input type="text" id="gender" name="gender" value="<?php echo $gender; ?>"></td>
</tr>

<tr>
<td><label for = "">Date Of Birth</label></td>
<td><input type="text" id="dob" name="dob" value="<?php echo $dob; ?>"></td>
</tr><tr>
<td><label for = "">Addres</label></td>
<td><input type="text" id="address" name="address" value="<?php echo $address; ?>"></td>
</tr><tr>
<td><label for = "">Country</label></td>
<td><input type="text" id="country" name="country" value="<?php echo $country; ?>"></td>
</tr><tr>
<td><label for = "">Bio</label></td>
<td><input type="text" id="bio" name="bio" value="<?php echo $bio; ?>"></td>
</tr>

<tr>
<td></td>
<td><input type="submit" id="update" name="update" value="Update"></td>
</tr>
</table>
</form>
</div>

Вот мой обновленный код, надеюсь, что-то вызвало это.