The proper reaction when you have a potential issue in your engineering

It was only discovered after a flight experienced the issue, though. It could have been much more serious.

But what does it say about their QA or lack of it?

Just to be clear, I’m not faulting Airbus. I take issues with the shallow snark at Boeing. The JetBlue incident was serious.

Airbus isn’t immune to controversies , like AF447 or Habsheem air show crash in 1988

Well "I ain't going" didn't let a mere crash or two stop them.