"__NSCFString navigationBar" : unrecognized selector sent to instance

Question

Alright Everyone,

I've got a real tough nut to crack. I am getting a very strange crash in my iOS app. During the sequence of closing a UIPopoverController by clicking off of it (on an iPad), this crash is occurring.

The really odd thing here is that it is a crash coming out of UIKit. I have filed a radar report for a very similar issue, but Apple marked it as closed and when asked, did not provide any further information than to say it was a duplicate of another issue (which I can not see).

Has anyone seen anything like this before?

EDIT 1: I can't figure out how to make the below a code block, the code block markup tool didn't do it. If anyone could point that out, that would be great :).

Thanks, ~Arash

-[__NSCFString navigationBar]: unrecognized selector sent to instance 0x7be4f510
2015-06-22 11:12:57.375 SpotlightEnterprise[82694:1472906] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFString navigationBar]: unrecognized selector sent to instance 0x7be4f510'
*** First throw call stack:
(
    0   CoreFoundation                      0x0522f746 __exceptionPreprocess + 182
    1   libobjc.A.dylib                     0x04e10a97 objc_exception_throw + 44
    2   CoreFoundation                      0x05237705 -[NSObject(NSObject) doesNotRecognizeSelector:] + 277
    3   CoreFoundation                      0x0517e287 ___forwarding___ + 1047
    4   CoreFoundation                      0x0517de4e _CF_forwarding_prep_0 + 14
    5   UIKit                               0x03506810 -[UINavigationItemView _updateLabelColor] + 45
    6   UIKit                               0x03507df3 -[UINavigationItemButtonView tintColorDidChange] + 86
    7   UIKit                               0x0377d28b -[_UITintColorVisitor _visitView:] + 363
    8   UIKit                               0x0377dab1 _UIViewVisitorEntertainVisitors + 98
    9   UIKit                               0x0377cb09 _UIViewVisitorRecursivelyEntertainDescendingVisitors + 166
    10  UIKit                               0x0377c859 +[_UIViewVisitor _startTraversalOfVisitor:withView:] + 377
    11  UIKit                               0x03484df1 -[UIView _receiveVisitor:] + 51
    12  UIKit                               0x0348a4dd -[UIView _dispatchTintColorVisitorWithReasons:] + 143
    13  UIKit                               0x0348a922 -[UIView setTintAdjustmentMode:] + 116
    14  UIKit                               0x03551433 -[UIPresentationController _enableOcclusion:] + 423
    15  UIKit                               0x035515d0 __55-[UIPresentationController _beginOcclusionIfNecessary:]_block_invoke + 44
    16  UIKit                               0x03c8208b -[_UIViewControllerTransitionCoordinator _applyBlocks:releaseBlocks:] + 198
    17  UIKit                               0x03c7e9b9 -[_UIViewControllerTransitionContext __runAlongsideAnimations] + 168
    18  UIKit                               0x03550f49 __56-[UIPresentationController runTransitionForCurrentState]_block_invoke392 + 67
    19  UIKit                               0x03481b3e -[UIViewAnimationState _runAlongsideAnimations] + 37
    20  UIKit                               0x03481182 -[UIViewAnimationState pop] + 36
    21  UIKit                               0x0347ff6e +[UIViewAnimationState popAnimationState] + 47
    22  UIKit                               0x0349ec6e +[UIView(UIViewAnimationWithBlocks) _setupAnimationWithDuration:delay:view:options:factory:animations:start:animationStateGenerator:completion:] + 518
    23  UIKit                               0x0349f017 +[UIView(UIViewAnimationWithBlocks) animateWithDuration:delay:options:animations:completion:] + 110
    24  UIKit                               0x03813b71 -[_UIPopoverAnimationController animateTransition:] + 384
    25  UIKit                               0x03550a8c __56-[UIPresentationController runTransitionForCurrentState]_block_invoke + 2315
    26  UIKit                               0x0358531b __40+[UIViewController _scheduleTransition:]_block_invoke + 18
    27  UIKit                               0x0343e862 ___afterCACommitHandler_block_invoke + 15
    28  UIKit                               0x0343e80d _applyBlockToCFArrayCopiedToStack + 415
    29  UIKit                               0x0343e622 _afterCACommitHandler + 549
    30  CoreFoundation                      0x0515086e __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 30
    31  CoreFoundation                      0x051507b0 __CFRunLoopDoObservers + 400
    32  CoreFoundation                      0x051461ea __CFRunLoopRun + 1226
    33  CoreFoundation                      0x05145a5b CFRunLoopRunSpecific + 443
    34  CoreFoundation                      0x0514588b CFRunLoopRunInMode + 123
    35  GraphicsServices                    0x05c1a2c9 GSEventRunModal + 192
    36  GraphicsServices                    0x05c1a106 GSEventRun + 104
    37  UIKit                               0x03414106 UIApplicationMain + 1526
    38  MyAppName                           0x000c841d main + 77
    39  libdyld.dylib                       0x057d5ac9 start + 1</code>