error generated with current ToDoLite-ios when deleting a list

[agonyou]

2015-06-02 23:38:25.169 ToDoLite[81037:7676495] * Terminating app due to uncaught exception 'NSRangeException', reason: 'Cannot remove an observer <MasterViewController 0x7fe5d3d13fb0> for the key path "rows" from <CBLLiveQuery 0x7fe5d1ca3d10> because it is not registered as an observer.' * First throw call stack: ( 0 CoreFoundation 0x000000010ed26c65 exceptionPreprocess + 165 1 libobjc.A.dylib 0x000000010e9bfbb7 objc_exception_throw + 45 2 CoreFoundation 0x000000010ed26b9d +[NSException raise:format:] + 205 3 Foundation 0x000000010e577a59 -[NSObject(NSKeyValueObserverRegistration) _removeObserver:forProperty:] + 608 4 Foundation 0x000000010e57775c -[NSObject(NSKeyValueObserverRegistration) removeObserver:forKeyPath:] + 90 5 Foundation 0x000000010e5857cb -[NSObject(NSKeyValueObserverRegistration) removeObserver:forKeyPath:context:] + 177 6 ToDoLite 0x000000010db54d49 -[MasterViewController viewWillDisappear:] + 217 7 UIKit 0x000000010f70903a -[UIViewController _setViewAppearState:isAnimating:] + 640 8 UIKit 0x000000010f72a37f -[UINavigationController _startCustomTransition:] + 865 9 UIKit 0x000000010f7363bf -[UINavigationController _startDeferredTransitionIfNeeded:] + 386 10 UIKit 0x000000010f736f0e -[UINavigationController viewWillLayoutSubviews] + 43 11 UIKit 0x000000010f881715 -[UILayoutContainerView layoutSubviews] + 202 12 UIKit 0x000000011f5e593e -[UILayoutContainerViewAccessibility layoutSubviews] + 43 13 UIKit 0x000000010f654a2b -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 536 14 QuartzCore 0x000000010f457ec2 -[CALayer layoutSublayers] + 146 15 QuartzCore 0x000000010f44c6d6 _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 380 16 QuartzCore 0x000000010f44c546 _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 24 17 QuartzCore 0x000000010f3b8886 _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 242 18 QuartzCore 0x000000010f3b9a3a _ZN2CA11Transaction6commitEv + 462 19 QuartzCore 0x000000010f3ba0eb _ZN2CA11Transaction17observer_callbackEP19CFRunLoopObservermPv + 89 20 CoreFoundation 0x000000010ec59ca7 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION + 23 21 CoreFoundation 0x000000010ec59c00 CFRunLoopDoObservers + 368 22 CoreFoundation 0x000000010ec4fa33 CFRunLoopRun + 1123 23 CoreFoundation 0x000000010ec4f366 CFRunLoopRunSpecific + 470 24 GraphicsServices 0x00000001127d1a3e GSEventRunModal + 161 25 UIKit 0x000000010f5d4900 UIApplicationMain + 1282 26 ToDoLite 0x000000010db5713f main + 111 27 libdyld.dylib 0x0000000110a2b145 start + 1 28 ??? 0x0000000000000001 0x0 + 1 ) libc++abi.dylib: terminating with uncaught exception of type NSException