Zend certified PHP/Magento developer

Product with customizable options returns a non-numeric exception in cart

I have a product with Customizable Options in the form of a dropdown on the product page. If I add the product to the cart without an option selected it works as would be expected, however if I add a product with one of the customizable options selected and navigate to the cart it returns the following error:

Exception #0 (Exception): Warning: A non-numeric value encountered in /var/www/vhosts/domain/htdocs/vendor/magento/module-catalog/Model/Product/Type/Price.php on line 527

It is worth noting that this error only occurs in the cart, I can by-pass the cart and proceed through the checkout without any issue.