Error message at the bottom of the page

Dear VillaTheme,

Thank you for your great plugins. I have three already and feel very satisfied with them. However recently, I have stumbled upon one probem with WooCommerce Boost Sales.

If you could please take a look at the product below:

At the very bottom you will notice an error message:
“Warning: A non-numeric value encountered in …/wp-content/plugins/woocommerce-boost-sales/includes/upsells.php on line 116”.

I do believe it has to do something with “Login to see the price” function (because when the User is logged in, that very same error message dissappears).

Would you be willing to look into my problem? Perhaps it’s not a huge modification that needs to take place?

I would highly appreciate your help.

Kind regards,
Andrzej