Undefined SECURE_AUTH_KEY/AUTH_KEY

On using the wp cli tool to maintain a WP 5.5.1 instance, with Virtue 3.4.2 as the active theme, I’m getting the following PHP Warnings returned:

PHP Warning: Use of undefined constant AUTH_KEY – assumed ‘AUTH_KEY’ (this will throw an Error in a future version of PHP) in /path/to/wp-content/themes/virtue/themeoptions/inc/class.redux_instances.php on line 67
Warning: Use of undefined constant AUTH_KEY – assumed ‘AUTH_KEY’ (this will throw an Error in a future version of PHP) in /path/to/wp-content/themes/virtue/themeoptions/inc/class.redux_instances.php on line 67
PHP Warning: Use of undefined constant SECURE_AUTH_KEY – assumed ‘SECURE_AUTH_KEY’ (this will throw an Error in a future version of PHP) in /path/to/wp-content/themes/virtue/themeoptions/inc/class.redux_instances.php on line 67
Warning: Use of undefined constant SECURE_AUTH_KEY – assumed ‘SECURE_AUTH_KEY’ (this will throw an Error in a future version of PHP) in /path/to/wp-content/themes/virtue/themeoptions/inc/class.redux_instances.php on line 67

I have AUTH_KEY and SECURE_AUTH_KEY defined with unique strings in wp-config.php as per the standard WP install instructions – any idea why I’m being thrown these warnings here?

The WP install and theme is otherwise vanilla with the following plugins:

20 installed plugins:
A akismet 4.1.6
A amazon-associates-link-builder 1.9.3
A better-search-replace 1.3.3
A contact-form-7 5.2.2
A cookie-notice 1.3.2
A expanding-archives 1.1.1
A google-analytics-dashboard-for-wp 6.2.2
A jetpack 8.9.1
A kadence-blocks 1.8.14
A kadence-importer 2.1.0
A mailchimp-for-wp 4.8.1
A pinterest-hover-pin-it-button 1.0
A pinterest-verify-meta-tag 1.3
A rss-image-feed 4.2.5
A virtue-toolkit 4.9.6
A wp-fail2ban 4.3.0.8
A wp-recipe-maker 6.5.1
A wp-super-cache 1.7.1
A wordpress-seo 14.9
D advanced-cache.php