I'm not a physicist or even a very smart man... but in this experiment, they did the math, knew what they were testing for, expected to see specific results... and didn't get those results.
To an outsider, it looks like they went about the project in a slightly wrong-headed way, in that they set up a test to prove what they thought was true. Which is not how science is supposed to work... you set up a test that creates the conditions in which your hypothesis could be proven correct; not a test designed to confirm a specific expected result.
So when the test didn't do what they expected, it is even more surprising. (If I am understanding this correctly.)
So I'm thinking faulty instrumentation, wonky data - i.e. the usual suspects that defeat some scientific hypothesis - is not the cause of this unexpected wobble.
Smarter people: Correct me if I'm wrong in any of this, please!