It says: Version: 6.3.1
I was already using 'five', so I changed the default order form to 'Premium Comparison' and that removed the first menu problem. But, when you get to the order form itself, the credit card drop down menu has the same issue. See screenshot.
I've tried this on Chrome and Microsoft Edge browsers on Windows 10 with same result in both. Because of the drop down menu, the order form cannot be completed. Is there a step by step walkthrough of setting up WHMCS? (all I've done is change the logo and add a single product and edit the nameserver section for people who want to use their own domain). The rest is straight out of the box.