This happened to me once, as in my first month at a new job, I came in one day to find I had caused a bug in production. But I hadn't deployed any software!

It turned out that the department had carefully orchestrated a system whereby all checked-in code would move automatically to alpha the next day, then beta, then production the next week. But nobody told me.

A manager there later told me, "If the code we write is strong enough, it does not need to be released--it will escape."

And the student understood.