Fix WHMCS Client dashboard invoice & services tab constant loading

We are having an issue where users aren't able to see their invoices or products due to the tab just constantly spinning loading.

We have attached the console error to give a general idea of what's happening. Our site is running the latest WHMCS with a custom theme (flat-7).

Research is pointing to this being our issue - https://www.carnfieldwebdesign.co.uk/blog/whmcs-fix-datatables-warning-table-idtableinvoiceslist-cannot-reinitialise-datatable/

You can see this error at baconfeet.com
User - test@baconfeet.com
Pass - password

This test user has one invoice and one product on their account. You will be unable to see them directly though due to the error. This is what we are trying to fix.