hello, we received a zombie crash which confused us long time, seems like double free, can you give us some advices about this crash? very confused , this crash can not be caught in xcode (instruments -> Zombie). this is full log, thx ! double free.crash

We have received a lots of crash reports in iOS15( 15.4.1, 15.4, 15.6), exception type is EXC_BAD_ACCESS (SIGSEGV) . Those crashes confused us very long time, please help us tracking issue, thank you ! This is crash thread, you can see full crash report below CoreFoundation _CFStringGetLength (in CoreFoundation) CFNetwork __CFNetworkErrorGetLocalizedDescription (in CFNetwork) CFNetwork __CFNetworkErrorGetLocalizedDescription (in CFNetwork) CFNetwork __CFNetworkErrorGetLocalizedDescription (in CFNetwork) CFNetwork __CFNetworkErrorGetLocalizedDescription (in CFNetwork) CFNetwork __CFNetworkErrorGetLocalizedDescription (in CFNetwork) CFNetwork __CFURLStorageSessionDisableCache (in CFNetwork) CFNetwork _CFURLRequestSetShouldStartSynchronously (in CFNetwork) CFNetwork _CFHTTPMessageCopyRequestURL (in CFNetwork) CFNetwork _CFURLCacheSetMemoryCapacity (in CFNetwork) CFNetwork _CFURLRequestSetHTTPHeaderFieldValue (in CFNetwork) CFNetwork _CFURLDownloadCancel (in CFNetwork) CFNetwork __CFNetworkErrorGetLocalizedDescription (in CFNetwork) CFNetwork __CFHTTPMessageSetResponseProxyURL (in CFNetwork) CFNetwork __CFNetworkHTTPConnectionCacheGetLimit (in CFNetwork) CFNetwork __CFNetworkErrorGetLocalizedDescription (in CFNetwork) CFNetwork _CFURLCacheSetDiskCapacity (in CFNetwork) libdispatch.dylib __dispatch_block_async_invoke2 (in libdispatch.dylib) libdispatch.dylib __dispatch_client_callout (in libdispatch.dylib) libdispatch.dylib __dispatch_lane_serial_drain (in libdispatch.dylib) libdispatch.dylib __dispatch_lane_invoke (in libdispatch.dylib) libdispatch.dylib __dispatch_workloop_invoke (in libdispatch.dylib) libdispatch.dylib __dispatch_workloop_worker_thread (in libdispatch.dylib) libsystem_pthread.dylib __pthread_wqthread (in libsystem_pthread.dylib) libsystem_pthread.dylib _start_wqthread (in libsystem_pthread.dylib) crash report.txt