Error: Failed to post to a semaphore (errno:15)

Hey, In the past couple of days I have started getting this error when running on the device. I am not sure what is the cause and cannot reproduce yet. Getting both `errno 15` and `errno 37`. No trace is reported, and no apparent crash or malfunction. Some google search shows all sorts of reasons, but I could not find any concrete hint as to which may be the cause. Only two things I changed recently are a new version of 2D Toolkit (and posted a question there as well) and iOS 7.1 Any help is appreciated.