Adding new menu entries fails

I activated debug mode and tried to add an individual link to my top menu which resulted in:
[10-May-2019 10:17:15 UTC] PHP Warning: Invalid argument supplied for foreach() in /mnt/web318/b1/45/58782945/htdocs/WordPress_SecureMode_01/wp-includes/wp-db.php on line 2363
(nothing is added to the menu)

The content of wp-db.php at line 2363
foreach ( $data as $field => $value ) {

conetxt:

	/**
	 * Prepares arrays of value/format pairs as passed to wpdb CRUD methods.
	 *
	 * @since 4.2.0
	 *
	 * @param array $data   Array of fields to values.
	 * @param mixed $format Formats to be mapped to the values in $data.
	 * @return array Array, keyed by field names with values being an array
	 *               of 'value' and 'format' keys.
	 */
	protected function process_field_formats( $data, $format ) {
		$formats = $original_formats = (array) $format;

		foreach ( $data as $field => $value ) {
			$value = array(
				'value'  => $value,
				'format' => '%s',
			);

			if ( ! empty( $format ) ) {
				$value['format'] = array_shift( $formats );
				if ( ! $value['format'] ) {
					$value['format'] = reset( $original_formats );
				}
			} elseif ( isset( $this->field_types[ $field ] ) ) {
				$value['format'] = $this->field_types[ $field ];
			}

			$data[ $field ] = $value;
		}

		return $data;
	}

Health summary:
https://pastebin.com/JWptWjkk

[ Please do not bump. ]

• This topic was modified 5 years, 5 months ago by theincogtion.

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