State restoration crash reports (decodeObject?) - ios

Question

I'm getting these crash reports from XCode (I pasted one at the bottom) and I can't reproduce the error or figure out what the problem is.
From the backtrace I'm thinking it could be related to the decodeObject stuff… I did have some problems with the new decodeBool and decodeDouble functions, so to be sure I made an NSCoder extension:
func safeDecodeDouble(key: String) -> Double? {
if self.containsValue(forKey: key) {
if let value = self.decodeObject(forKey: key) as? Double {
return value
}
return self.decodeDouble(forKey: key)
}
return nil
}
func safeDecodeBool(key: String) -> Bool? {
if self.containsValue(forKey: key) {
if let value = self.decodeObject(forKey: key) as? Bool {
return value
}
return self.decodeBool(forKey: key)
}
return nil
}
func safeDecodeDate(key: String) -> Date? {
if self.containsValue(forKey: key) {
if let value = self.decodeObject(forKey: key) as? Date {
return value
}
}
return nil
}
func safeDecodeString(key: String) -> String? {
if self.containsValue(forKey: key) {
if let value = self.decodeObject(forKey: key) as? String {
return value
}
}
return nil
}
Now I only use the safeDecode functions in my code, but I'm still getting those same crash reports.
The third item in the backtrace says [UIStoryboard storyboardWithName:bundle:], but I don't know what that could have to do with anything. Also every crash report has something about state restoration and decodeObject, so I'm thinking the problem isn't the storyboard instantiation per se.
At the same time I never have any problems when I test state restoration on the simulator or on my devices, so apparently it's only happening to some people.
Any ideas on what could be going on here?
Last Exception Backtrace:
0 CoreFoundation 0x18a146fd8 __exceptionPreprocess + 124 (NSException.m:165)
1 libobjc.A.dylib 0x188ba8538 objc_exception_throw + 56 (objc-exception.mm:521)
2 UIKit 0x190a36850 +[UIStoryboard storyboardWithName:bundle:] + 776 (UIStoryboard.m:99)
3 UIKit 0x190bfacfc -[_UIStoryboardProxy initWithCoder:] + 192 (UIStateRestorationSupport.m:324)
4 Foundation 0x18ab96420 _decodeObjectBinary + 2076 (NSKeyedArchiver.m:2304)
5 Foundation 0x18ab95b58 _decodeObject + 308 (NSKeyedArchiver.m:2467)
6 UIKit 0x1903e62ec -[UIStateRestorationKeyedUnarchiver decodeObjectForKey:] + 88 (UIStateRestorationSupport.m:454)
7 UIKit 0x1903e5ba8 -[UIApplication(StateRestoration) _restoreApplicationPreservationStateWithSessionIdentifier:beginHandler:completionHandler:] + 4772 (UIApplication.m:13551)
8 UIKit 0x1902e76b4 -[UIApplication(StateRestoration) _doRestorationIfNecessary] + 244 (UIApplication.m:13979)
9 UIKit 0x1902e7288 -[UIApplication _handleDelegateCallbacksWithOptions:isSuspended:restoreState:] + 296 (UIApplication.m:1792)
10 UIKit 0x1904f3800 -[UIApplication _callInitializationDelegatesForMainScene:transitionContext:] + 3452 (UIApplication.m:2129)
11 UIKit 0x1904f92a8 -[UIApplication _runWithMainScene:transitionContext:completion:] + 1684 (UIApplication.m:3625)
12 UIKit 0x19050dde0 __84-[UIApplication _handleApplicationActivationWithScene:transitionContext:completion:]_block_invoke.3151 + 48 (UIApplication.m:10365)
13 UIKit 0x1904f653c -[UIApplication workspaceDidEndTransaction:] + 168 (UIApplication.m:2990)
14 FrontBoardServices 0x18bcef884 __FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__ + 36 (FBSSerialQueue.m:158)
15 FrontBoardServices 0x18bcef6f0 -[FBSSerialQueue _performNext] + 176 (FBSSerialQueue.m:177)
16 FrontBoardServices 0x18bcefaa0 -[FBSSerialQueue _performNextFromRunLoopSource] + 56 (FBSSerialQueue.m:206)
17 CoreFoundation 0x18a0f5424 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 24 (CFRunLoop.c:1943)
18 CoreFoundation 0x18a0f4d94 __CFRunLoopDoSources0 + 540 (CFRunLoop.c:1989)
19 CoreFoundation 0x18a0f29a0 __CFRunLoopRun + 744 (CFRunLoop.c:2821)
20 CoreFoundation 0x18a022d94 CFRunLoopRunSpecific + 424 (CFRunLoop.c:3113)
21 UIKit 0x1902e045c -[UIApplication _run] + 652 (UIApplication.m:2658)
22 UIKit 0x1902db130 UIApplicationMain + 208 (UIApplication.m:4089)
23 Leio 0x1000b6ecc main + 120 (BookInfoTableViewController.swift:19)
24 libdyld.dylib 0x18903159c start + 4
Edit: Here's a different crash report that showed up and suggests there really is a problem with state restoration. I can never reproduce it myself, though. :/
0 CoreFoundation 0x18385adb0 __exceptionPreprocess + 124 (NSException.m:162)
1 libobjc.A.dylib 0x182ebff80 objc_exception_throw + 56 (objc-exception.mm:531)
2 Foundation 0x1841d4704 -[NSCoder(Exceptions) __failWithException:] + 132 (NSCoder.m:544)
3 Foundation 0x1841d48bc -[NSCoder(Exceptions) __failWithExceptionName:errorCode:format:] + 440 (NSCoder.m:580)
4 Foundation 0x1841a33b8 _decodeObjectBinary + 2996 (NSKeyedArchiver.m:2173)
5 Foundation 0x1841a274c _decodeObject + 304 (NSKeyedArchiver.m:2313)
6 UIKit 0x188b3e20c -[UIStateRestorationKeyedUnarchiver decodeObjectForKey:] + 88 (UIStateRestorationSupport.m:454)
7 UIKit 0x188b3daf8 -[UIApplication(StateRestoration) _restoreApplicationPreservationStateWithSessionIdentifier:beginHandler:completionHandler:] + 4908 (UIApplication.m:15043)
8 UIKit 0x188a32d44 -[UIApplication(StateRestoration) _doRestorationIfNecessary] + 244 (UIApplication.m:15471)
9 UIKit 0x188a32964 -[UIApplication _handleDelegateCallbacksWithOptions:isSuspended:restoreState:] + 308 (UIApplication.m:1860)
10 UIKit 0x188c62184 -[UIApplication _callInitializationDelegatesForMainScene:transitionContext:] + 2904 (UIApplication.m:2112)
11 UIKit 0x188c665f0 -[UIApplication _runWithMainScene:transitionContext:completion:] + 1684 (UIApplication.m:3355)
12 UIKit 0x188c63764 -[UIApplication workspaceDidEndTransaction:] + 168 (UIApplication.m:2748)
13 FrontBoardServices 0x1851fb7ac __FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__ + 36 (FBSSerialQueue.m:158)
14 FrontBoardServices 0x1851fb618 -[FBSSerialQueue _performNext] + 168 (FBSSerialQueue.m:177)
15 FrontBoardServices 0x1851fb9c8 -[FBSSerialQueue _performNextFromRunLoopSource] + 56 (FBSSerialQueue.m:206)
16 CoreFoundation 0x18381109c __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 24 (CFRunLoop.c:1761)
17 CoreFoundation 0x183810b30 __CFRunLoopDoSources0 + 540 (CFRunLoop.c:1807)
18 CoreFoundation 0x18380e830 __CFRunLoopRun + 724 (CFRunLoop.c:2536)
19 CoreFoundation 0x183738c50 CFRunLoopRunSpecific + 384 (CFRunLoop.c:2814)
20 UIKit 0x188a2b94c -[UIApplication _run] + 460 (UIApplication.m:2578)
21 UIKit 0x188a26088 UIApplicationMain + 204 (UIApplication.m:3772)
22 Leio 0x1000f6ecc main + 120 (BookInfoTableViewController.swift:19)
23 libdyld.dylib 0x1832d68b8 start + 4 (start_glue.s:78)