here is the thread backtrace:
Process 2636 stopped
* thread #18, name = 'QSGRenderThread', stop reason = EXC_BREAKPOINT (code=1, subcode=0x19ea5a3ec)
frame #0: 0x000000019ea5a3ec libsystem_c.dylib`__abort + 160
libsystem_c.dylib`__abort:
-> 0x19ea5a3ec <+160>: brk #0x1
libsystem_c.dylib`abort_report_np:
0x19ea5a3f0 <+0>: pacibsp
0x19ea5a3f4 <+4>: sub sp, sp, #0x30
0x19ea5a3f8 <+8>: stp x20, x19, [sp, #0x10]
(lldb) bt
* thread #18, name = 'QSGRenderThread', stop reason = EXC_BREAKPOINT (code=1, subcode=0x19ea5a3ec)
* frame #0: 0x000000019ea5a3ec libsystem_c.dylib`__abort + 160
frame #1: 0x000000019ea5a34c libsystem_c.dylib`abort + 180
frame #2: 0x0000000103b9c060 libclang_rt.asan_osx_dynamic.dylib`__sanitizer::Abort() + 68
frame #3: 0x0000000103b9b728 libclang_rt.asan_osx_dynamic.dylib`__sanitizer::Die() + 212
frame #4: 0x0000000103b9b7d0 libclang_rt.asan_osx_dynamic.dylib`__sanitizer::CheckFailed(char const*, int, char const*, unsigned long long, unsigned long long) + 156
frame #5: 0x0000000103b9c190 libclang_rt.asan_osx_dynamic.dylib`__sanitizer::UnsetAlternateSignalStack() + 100
frame #6: 0x0000000103b86a8c libclang_rt.asan_osx_dynamic.dylib`__asan::AsanThread::Destroy() + 252
frame #7: 0x000000019eb1db88 libsystem_pthread.dylib`_pthread_tsd_cleanup + 448
frame #8: 0x000000019eb20968 libsystem_pthread.dylib`_pthread_exit + 84
frame #9: 0x000000019eb20278 libsystem_pthread.dylib`_pthread_start + 160