App crashes after some swipes

[castvoid]

Here is the exception thrown:

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[__NSPlaceholderArray initWithObjects:count:]: attempt to insert nil object from objects[0]'
*** First throw call stack:
(0x18316a084 0x192d1c0e4 0x183053300 0x18305f5b8 0x10006a120 0x187980a74 0x100069fb4 0x100068728 0x1877d7f08 0x1877d7a70 0x1877d7978 0x1870fd874 0x100201118 0x100205130 0x1831218dc 0x18311f984 0x18304d664 0x18c07f5a4 0x187806164 0x10006fe3c 0x193392a08)
libc++abi.dylib: terminating with uncaught exception of type NSException