See, that's the kind of mean spirited reading of texts I hate so much. They were made aware of the issue, they looked at the code and (they claim) that it doesn't behave as designed because of a bug. This is them saying "We didn't design the cache to never be purged, that's a bug." Whether you believe that or not is your own problem but that's the whole story, writing "a bug we uncovered" is entirely appropriate in that context.
The charitable reading is that regardless of who "discovered" or "reported" the symptoms of the bug, Apple's engineers "uncovered" it in terms of isolating and diagnosing the precise issue at the source level.
(It's also possible - even likely - that Apple already knew about the bug. Apple does quite a lot of QA and every product ever shipped has had known bugs that weren't deemed so important as to postpone release.)
Two lies: the "bug" was uncovered a considerable time ago (August 2010 was when I read the first story talking about it) and was first exposed by third-parties (so if Apple did "uncover" it, they've been sitting on this discover for some time).
You speak of the symptoms of the bug as if they were the bug, consider this one act play:
• The internet claims Apple is tracking all iPhone owners!
• Steve Jobs interrupts family time to exclaim "WTF!"
• SJ: "Minion! Verify this claim!"
• Minion: "It is true, to the extent that we keep large, possibly unbounded, volumes of cell tower and wifi access point in the cache for the purpose of…" SNICKER-SNACK… thump.
• SJ: "Engineering, fix this. Marketing, communicate this.", returns to family time.
• Engineering to engineer: "Fix this."
• Engineer to self: "I do not know why this happens, I will search and uncover this bug." <<<--- there, that is where the bug is uncovered. He fixes the purge code from whatever simple or broken strategy the first coder used, perhaps deleting the comment that says "// might need to prune the cache, but the OS probably does that when it gets too big"
• Marketing: "What? We were busy hiding the links on the home page until you respect our new iPad2, but ok, we can crank out a press release if it saves us from the vorpal blade."
DOWN CURTAIN // insert character development and pathos before first rehearsal
A bug _you_ uncovered?