's IT scope is huge, few people appreciate what it is and how it gets done. eBay
's infrastructure includes more than 25,000 Sun and IBM servers. They process over 250 checkouts per second 24/7/365 AND handle peaks even larger than that; on a daily basis eBay
processes tens of billions of requests daily through their platform. They currently have over 70,000 software developers, a new version of their site is pushed out every two weeks. You cannot imagine what it takes in terms of revision control, management of the SDK tools and environments, and the sandbox test environments needed to test a small software change.
Also keep in mind that no company in the world can replicate all the custom computers and devices and their configurations. So sandbox testing is done with 'virgin' (fresh installs of all software) operating systems, operating system versions, and browsers. It is often impossible to even replicate the issue that users see in their computers, and if you cannot replicate the issue fixing it is nearly impossible (not saying this is the case here, I am not that familiar with this specific issue).