Well, glad you upgraded from such an old version. My understanding is that likely it had security issues. My recommendation would be to use this previously unavailable information to take action on your site. Take a look at the errors and see what commonalities exist. Perhaps that (or those) ip addresses need to be reported to the respective host(s) about how they are trying to abuse your site, and then maybe also have the address(es) blocked from your site through your .htaccess file(s). Afterall, if they're not engaging with your site appropriately then either they shouldn't be able to or maybe they have an issue that needs to be corrected. Take a look at the product_id identified and review your database through your myPHPAdmin panel, do you have a product_id of 13493? (Or could look through your store to find the same.) My guess is that no, you don't have 13,493 items and therefore don't have a product_id that high, which further indicates that it's not actually your cart providing that URL, but someone/something providing that to your cart to attempt to abuse it.
Realize, ignoring the abusive behavior won't resolve anything, and it may even escalate.
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