Software Code Reviews?
It doesn't say much for their software management processes. If you've got a couple of engineers with an idea, they have to spend time developing the algorithm to recognise and defeat the test, then check it out by seeing if it's capable of recognising test conditions reliably enough to be useful. All this takes time and resources, which presumably the management didn't notice?
Then you have the formal code review before you release production code. Generally this involves letting other people look at your source code, may require you to have all your curly brackets in the correct place and use the correct combination of tabs and spaces and possibly even go through the functionality of the code and check out the results of your regression tests. Then you get the reviewers to sign off that it's OK and does what is required. All without them noticing the big block of source, the function of which wasn't clearly explained.
Yes, clearly the work of a couple of rogue software engineers who are capable of amazing feats when it comes to hoodwinking the system.