Laravel/PHP: Unidentified index that does exist - php

Question

I have an object with a property:
protected $recipients = array();
In one of my methods I set the contents of the $recipients property with an associative array of data using this method:
public function setRecipientData($recipientData){
foreach($recipientData as $key => $value){
$this->recipients[$key] = $value;
}
}
When I dump the contents of $this->recipients, the array ends up looking like this:
array (size=2)
0 =>
array (size=6)
'email' => string 'info#mycompany.com' (length=29)
'userEmail' => string 'xxx#yyy.com' (length=11)
'first_name' => string 'Test' (length=4)
'last_name' => string 'User' (length=4)
'jobTitle' => string 'Customer User' (length=13)
'phoneNumber' => string '123.456.7890' (length=12)
I also have a property that will extract only the email addresses from the property like this:
private function getRecipientEmails(){
$emails = array();
foreach($this->recipients as $recipient){
$emailPair = array('email' => $recipient['userEmail']);
$emails[] = $emailPair;
}
return $emails;
}
The problem that I'm running into is that when I run the method getRecipientsEmails() I get the error:
Undefined index: userEmail
I don't understand why it's not seeing the index 'userEmail'. If I dump the nested array it shows a value:
private function getRecipientEmails(){
$emails = array();
foreach($this->recipients as $recipient){
dd($emailPair = array('email' => $recipient['userEmail']));
$emails[] = $emailPair;
}
return $emails;
}
Result:
array (size=1)
'email' => string 'xxx#yyy.com' (length=20)
I've tried dumping the autoload with composer but it makes no difference.
Can anyone help point me in the right direction??
EDIT: Sorry, I realized that I wrote the wrong method into my original post. I've added the original getRecipientEmails() method and the dump that shows the data.