iOS App crash on version 15.8.4

Question

My iOS app crash on version 15.8.4 and getting this error-

Objective-C exception thrown.  Name: NSInvalidArgumentException Reason: -[UIBarButtonItem initWithBarButtonSystemItem:primaryAction:menu:]: unrecognized selector sent to instance 0x7fadc1a8e240
Native stack trace:
	0   CoreFoundation                      0x00007fff20405604 __exceptionPreprocess + 242
	1   libobjc.A.dylib                     0x00007fff201a4a45 objc_exception_throw + 48
	2   CoreFoundation                      0x00007fff204145ba +[NSObject(NSObject) instanceMethodSignatureForSelector:] + 0
	3   CoreFoundation                      0x00007fff20409bbf ___forwarding___ + 1471
	4   CoreFoundation                      0x00007fff2040bd48 _CF_forwarding_prep_0 + 120
	5   libxamarin-dotnet-debug.dylib       0x000000011143c6f9 xamarin_dyn_objc_msgSend + 217
	6   libmonosgen-2.0.dylib               0x000000011181977c do_icall + 348
	7   libmonosgen-2.0.dylib               0x0000000111817c57 do_icall_wrapper + 295
	8   libmonosgen-2.0.dylib               0x0000000111807de7 mono_interp_exec_method + 3271
	9   libmonosgen-2.0.dylib               0x0000000111805714 interp_runtime_invoke + 260
	10  libmonosgen-2.0.dylib               0x00000001118f5437 mono_runtime_invoke_checked + 135
	11  libmonosgen-2.0.dylib               0x00000001118f9138 mono_runtime_invoke + 552
	12  libxamarin-dotnet-debug.dylib       0x0000000111433d1d xamarin_invoke_trampoline + 6397
	13  libxamarin-dotnet-debug.dylib       0x000000011143b119 xamarin_arch_trampoline + 105
	14  libxamarin-dotnet-debug.dylib       0x000000011143c57a xamarin_x86_64_common_trampoline + 118
	15  UIKitCore                           0x00007fff25669e32 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 1646
	16  QuartzCore                          0x00007fff28a87431 _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 543
	17  QuartzCore                          0x00007fff28a92609 _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 65
	18  QuartzCore                          0x00007fff289b48ed _ZN2CA7Context18commit_transactionEPNS_11TransactionEdPd + 623
	19  QuartzCore                          0x00007fff289ebf6e _ZN2CA11Transaction6commitEv + 774
	20  QuartzCore                          0x00007fff289ed1ec _ZN2CA11Transaction25flush_as_runloop_observerEb + 60
	21  CoreFoundation                      0x00007fff203712f1 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23
	22  CoreFoundation                      0x00007fff2036bab5 __CFRunLoopDoObservers + 570
	23  CoreFoundation                      0x00007fff2036c04d __CFRunLoopRun + 1100
	24  CoreFoundation                      0x00007fff2036b704 CFRunLoopRunSpecific + 562
	25  GraphicsServices                    0x00007fff2cba9c8e GSEventRunModal + 139
	26  UIKitCore                           0x00007fff2509e65a -[UIApplication _run] + 928
	27  UIKitCore                           0x00007fff250a32b5 UIApplicationMain + 101
	28  libxamarin-dotnet-debug.dylib       0x00000001113fca8a xamarin_UIApplicationMain + 58
	29  libmonosgen-2.0.dylib               0x000000011181977c do_icall + 348
	30  libmonosgen-2.0.dylib               0x0000000111817c57 do_icall_wrapper + 295
	31  libmonosgen-2.0.dylib               0x0000000111807de7 mono_interp_exec_method + 3271
	32  libmonosgen-2.0.dylib               0x0000000111805714 interp_runtime_invoke + 260
	33  libmonosgen-2.0.dylib               0x00000001118f5437 mono_runtime_invoke_checked + 135
	34  libmonosgen-2.0.dylib               0x00000001118fc6e5 mono_runtime_exec_main_checked + 117
	35  libmonosgen-2.0.dylib               0x000000011175ef26 mono_jit_exec + 358
	36  libxamarin-dotnet-debug.dylib       0x000000011143afd1 xamarin_main + 1601
	37  XXXXAppName                         0x000000010ef5aa74 main + 52
	38  dyld                                0x000000010f556f21 start_sim + 10
	39  ???                                 0x00000001154bd530 0x0 + 4652258608

Answer 1

UI-Kit uses Objective-c style dynamic binding (lookup method by name). The selector name was passed to c# binding library, but the method was not found. Simple coding error.