Back end? I thought the only problem was the data. I associate "backend" with server-side code, not actual raw data.

Weird that people are voting you down. I develop backend systems for a living and also would separate a data problem from a backend problem.

Let's be clear here. Apple has a data problem.

I develop backend systems too. The data is not separate from the system. No one gives me a pass when the data is bad.

Even if the data is provided by a third party and you have no control over it?

You do have some control over it, by choosing which third part(y|ies) you work with.