Our only logical conclusion was the the laws of chemistry and physics had changed this week and nobody informed us (or our clients).
All kidding aside, I've heard the same comments - "nothing's changed" - everywhere I've worked and it is a serious issue as something has changed. It just means you need to look a little further into what's going on.
What really should be said instead of "nothing's changed" is this:
"Everything that we are keeping an eye on has not changed; something that we are not keeping an eye on has changed and it is ruining everything."
And that's totally different from "nothing's changed". Knowing that, the whole mindset quickly changes and people start thinking more freely.