Your plugin seems to generate a wordpress error log

Hi,

I have been trouble shooting why we do receive error log on the server everytime the customer visit a category on our site.

The error is like this:

[STDERR] PHP Warning: Undefined array key “default” in /xxx.com/public_html/wp-includes/class-wp-list-util.php on line 170

Here is line 170 in that file:

$newlist[ $key ] = $value[ $field ];

Here is that part of the script:

/**
	 * Plucks a certain field out of each element in the input array.
	 *
	 * This has the same functionality and prototype of
	 * array_column() (PHP 5.5) but also supports objects.
	 *
	 * @since 4.7.0
	 *
	 * @param int|string $field     Field to fetch from the object or array.
	 * @param int|string $index_key Optional. Field from the element to use as keys for the new array.
	 *                              Default null.
	 * @return array Array of found values. If $index_key is set, an array of found values with keys
	 *               corresponding to $index_key. If $index_key is null, array keys from the original
	 *               $list will be preserved in the results.
	 */
	public function pluck( $field, $index_key = null ) {
		$newlist = array();

		if ( ! $index_key ) {
			/*
			 * This is simple. Could at some point wrap array_column()
			 * if we knew we had an array of arrays.
			 */
			foreach ( $this->output as $key => $value ) {
				if ( is_object( $value ) ) {
					$newlist[ $key ] = $value->$field;
				} elseif ( is_array( $value ) ) {
					$newlist[ $key ] = $value[ $field ];
				} else {
					_doing_it_wrong(
						__METHOD__,
						__( 'Values for the input array must be either objects or arrays.' ),
						'6.2.0'
					);
				}
			}

			$this->output = $newlist;

			return $this->output;
		}

When I have your plugin activated the error starts on the server log, when I deactivate your plugin it goes away. Please look at why this occur.

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