I'm seeing this too, it started recently, I guess with an Xcode update. My MacOS app is using CoreImage / NSImage a lot. The stack trace usually ends in: std::__1::__hash_table<std::__1::__hash_value_type<long, qos_info_t> [..], qosWaiterSignallerInvariantCheck, etc... I haven't seen the crash yet in production, but I see it very easily in a debug build, within a few minutes. Any help would be appreciated.