This article is mostly ********. 1 sprint is 2 weeks minimum. If they're running agile sprints, it's at least 4 weeks (2 sprints) to get stuff done.
Article is obviously written by non techie.
What really happened was probably this, upper management had a meeting with QA and top level software execs, started identifying a huge surplus of bugs (I'm sure Apple employees themselves have noticed)
They then spend several weeks to months prioritizing these bugs, making sure they are carefully identified and easily produced. Then have an action plan to fix these in the next quarter.
Some bugs take minutes, some bugs take weeks, some need some major rewrite.
I'm guessing the week downtime is basically to do the first part, stop production of new bugs, have the teams sit down and carefully analyze areas of improvement, parts that need to be fixed, rewritten, refactored, then start up the development again.