SDWebImage: Crash at -[SDWebImageDownloaderOperation start]

After updating to e8c5ed17c01de9bcfe330b974561f0ec94b49286 from a very old version, I started to see a crash with following stack trace. This is iOS 6, so far happened with iPhone 4S & iPhone5.

Fatal Exception NSInvalidArgumentException
-[**NSSetI postUpdatesIfNecessary]: unrecognized selector sent to instance 0x1fdd7d00
0    CoreFoundation  __exceptionPreprocess + 162
1    libobjc.A.dylib     objc_exception_throw + 30
2    CoreFoundation  -[NSObject(NSObject) doesNotRecognizeSelector:] + 170
3    CoreFoundation  ___forwarding_** + 392
4    CoreFoundation  _CF_forwarding_prep_0 + 24
5    CoreTelephony   ___SendInternalNotification_sync_block_invoke_0 + 32
6 ...    CoreFoundation  __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ + 14
7    CoreFoundation  __CFRunLoopDoTimer + 272
8    CoreFoundation  __CFRunLoopRun + 1232
9    CoreFoundation  CFRunLoopRunSpecific + 356
10   CoreFoundation  CFRunLoopRun + 98
11   wanelo      -[SDWebImageDownloaderOperation start]
12   Foundation  __block_global_6 + 102
13 ...   libdispatch.dylib   _dispatch_call_block_and_release + 10
14   libdispatch.dylib   _dispatch_root_queue_drain + 252
15   libdispatch.dylib   _dispatch_worker_thread2 + 84
16   libsystem_c.dylib   _pthread_wqthread + 360
17   libsystem_c.dylib   start_wqthread + 8