Update State.php

Declare module namespace before template path

Author: mageprince

app/code/Magento/LayeredNavigation/Block/Navigation/State.php

@@ -17,7 +17,7 @@ class State extends \Magento\Framework\View\Element\Template
     /**
      * @var string
      */
-    protected $_template = 'layer/state.phtml';
+    protected $_template = 'Magento_LayeredNavigation::layer/state.phtml';
 
     /**
      * Catalog layer