Error: Call to a member function bundle() on null drupal8_w3css_theme_preprocess_html()

Problem/Motivation

Error occurs when anonymous visitor clicks on link to missing page from ols serach results. Website becomes unavailable, WSOD.
themes/d8w3css/drupal8_w3css_theme.theme ligne 37

Steps to reproduce

Click on any non-exiostent page link

Proposed resolution

No fix

Remaining tasks

User interface changes

API changes

Data model changes