PHP: Undefined index error when accessing array index from for each loop to use in an outside array?

Question

Why is this happening? I keep getting an error on this line of code: $groupcondition = $filter['conditions'][$index]; with the error message Undefined index: conditions. It clearly exists. Using Laravel to create columns. The conditions array is inside of the parent filter array, there is a parent filter array and a child filter array.

dump($filter):

  "filter" => array:3 [▶
    0 => array:1 [▶
      0 => array:3 [▶
        "code" => array:1 [▶
          "code" => "Thank You Codes"
        ]
        "condition" => array:1 [▶
          "condition" => "AND"
        ]
        "value" => array:2 [▶
          "title" => "BD"
          "desc" => "Board Member"
        ]
      ]
    ]
    1 => array:1 [▶
      0 => array:3 [▶
        "code" => array:1 [▶
          "code" => "Thank You Codes"
        ]
        "condition" => array:1 [▶
          "condition" => "AND"
        ]
        "value" => array:2 [▶
          "title" => "AU"
          "desc" => "Auction Donation Thank You"
        ]
      ]
    ]
    2 => array:1 [▶
      0 => array:3 [▶
        "code" => array:1 [▶
          "code" => "Thank You Codes"
        ]
        "condition" => array:1 [▶
          "condition" => "AND"
        ]
        "value" => array:2 [▶
          "title" => "AM123"
          "desc" => "am 123"
        ]
      ]
    ]
  ]
  "conditions" => array:3 [▶
    0 => array:1 [▶
      "condition" => "AND"
    ]
    1 => array:1 [▶
      "condition" => "OR"
    ]
    2 => array:1 [▶
      "condition" => "AND"
    ]
  ]
]

Function:

public function createCampaign($filter, $new_campaign)
    {
        foreach ($filter['filter'] as $index => $group) {
            $groupcondition = $filter['conditions'][$index];
            $filtergroup = FilterGroups::create([
                'campaign_id' => $new_campaign->id,
                'condition' => $groupcondition['condition']
            ]);
            foreach ($group as $filter) {
                $field = $filter['code']['code'];
                // change field name to donor perfect column name
                if ($field == 'Thank You Codes') {
                    $field = 'ty_letter_no';
                } else if ($field == 'General Ledger Codes') {
                    $field = 'gl_code';
                } else if ($field == 'Campaign Codes') {
                    $field = 'campaign';
                } else if ($field == 'Solicit Codes') {
                    $field = 'solicit_code';
                } else {
                    $field = 'sub_solicit_code';
                }

                Filters::create([
                    'filter_id' => $filtergroup->id,
                    'field' => $field,
                    'value' => $filter['value']['title'],
                    'condition' => $filter['condition']['condition']
                ]);
            };
        }
    }