I experienced a bug today when booking an international flight with travel certificate. The flight actually costs less than my travel certificate value. After entering certificate, the site gave out right information in cost/deduction; however the booking couldn’t proceed further because the site kept on giving error messages for other forms of payment (and the default credit card row was no longer available).

I tried a few times using Firefox and Internet Explorer, but neither worked. Decided to call United, and was on hold hoping to talk with web support, then I tried one more time with Chrome and coincidentally it gave me the old web interface and I was able to complete the booking. It was frustrating as I was searching for an almost last minute flight.