Today I encountered a strange crash in the system above iOS14.FontAssetDownloadManager crash. Fatal Exception: NSInvalidArgumentException -[__NSCFNumber compare:]: nil argument Fatal Exception: NSInvalidArgumentException 0 CoreFoundation 0x189a699d8 __exceptionPreprocess 1 libobjc.A.dylib 0x19ddecb54 objc_exception_throw 2 CoreFoundation 0x189ad3d98 -[__NSCFString characterAtIndex:].cold.1 3 CoreFoundation 0x189ad4018 -[__NSCFBoolean compare:].cold.1 4 CoreFoundation 0x189956c0c +[NSArray array] 5 CoreFoundation 0x1899557f4 -[__NSCFNumber isEqualToNumber:] 6 CoreText 0x18dcb1480 +[FontAssetDownloadManager filterIncompatibleAsset:] 7 CoreText 0x18dcb182c +[FontAssetDownloadManager availableMobileAssetsWithOptions:error:] 8 CoreText 0x18dcb1d44 +[FontAssetDownloadManager availableMobileAssetsWithOptions:manager:error:] 9 CoreText 0x18dcafde4 -[FontAssetDownloadManager mobileAssetsForUnmatched:] 10 CoreText 0x18dcafb04 -[FontAssetDownloadManager downloadFontAssets] 11 CoreText 0x18dcb3e5c __CTFontDescriptorMatchFontDescriptorsWithProgressHandler_block_invoke 12 libdispatch.dylib 0x1896a1298 _dispatch_call_block_and_release 13 libdispatch.dylib 0x1896a2280 _dispatch_client_callout 14 libdispatch.dylib 0x18964adcc _dispatch_lane_serial_drain$VARIANT$mp 15 libdispatch.dylib 0x18964b8a8 _dispatch_lane_invoke$VARIANT$mp 16 libdispatch.dylib 0x189655338 _dispatch_workloop_worker_thread 17 libsystem_pthread.dylib 0x1d224d5a4 _pthread_wqthread 18 libsystem_pthread.dylib 0x1d2250874 start_wqthread