So, a few years ago I was working at a small state government department. After we has suffered a major development infrastructure outage (another story), I was so outspoken about what a shitty job the infrastructure vendor was doing, the IT Director put me in charge of managing the environment and the vendor, even though I was actually a software architect.
Anyway, a year later, we get a new project manager, and she decides that she needs to bring in a new team of contract developers because she doesn't trust us incumbents.
They develop a new application, but won't use our test team, insisting that their "BA" can do the testing themselves.
Finally it goes into production.
And crashes on Day 1. And keeps crashing.
Its the infrastructure goes out the cry from her office, do something about it!
I check the logs, can find nothing wrong, just this application keeps crashing.
I and another dev ask for the source code so that we can see if we can help find their bug, but we are told in no uncertain terms that there is no bug, they don't need any help, and we must focus on fixing the hardware issue.
After a couple of days of this, she called a meeting, all the PMs, the whole of the other project team, and me and my mate. And she starts laying into us about how we are letting them all down.
We insist that they have a bug, they insist that they can't have a bug because "it's been tested".
This ends up in a shouting match when my mate lost his cool with her.
So, we went back to our desks, got the exe and the pdb files (yes, they had published debug info to production), and reverse engineered it back to C# source, and then started looking through it.
Around midnight, we spotted the bug.
We took it to them the next morning, and it was like "Oh". When we asked how they could have tested it, they said, ah, well, we didn't actually test that function as we didn't think it would be used much....
What happened after that?
Not a happy ending. Six months later the IT Director retires and she gets shoed in as the new IT Director and then starts a bullying campaign against the two of us until we quit.