xcode - What does "Class _NSZombie_OS_voucher is implemented in both ?? and ??" mean? -

i got following message in xcode when had both address sanitizer , zombie objects enabled in scheme's diagnostics options, , ran project:

objc[656]: class _nszombie_os_voucher implemented in both ?? , ??. 1 of 2 used. 1 undefined. 

i disabled zombie objects , above message went away, won't come if turn zombie objects on.

what message mean?

the comment vaticrite helpful.

stop app , clean project.

from simulator click 'simulator' , 'reset content , settings'