Reproduction steps:
1. Open and run the attached 'macOS.zip' application.
- Crash.

(If the application doesn't crash)
2. Restart a PC.
3. Run a heavy memory and CPU usage process in the background.
4. Use a windowed resolution and reduce the window size.

Alternate reproduction steps (low chance of reproduction):
1. Open the attached '...s_UnityProj.zip' Unity project.
2. Build and run it as macOS standalone.

Call stack:
0 ??? 0x00000001169dba09 0 + 4674402825
1 ??? 0x00000001169db4a2 0 + 4674401442
2 ??? 0x00000001169db060 0 + 4674400352
3 ??? 0x000000010d7ca231 0 + 4521239089
4 libmono.0.dylib 0x000000010fd0a0c6 mono_jit_runtime_invoke + 1766
5 libmono.0.dylib 0x000000010fe36a06 mono_runtime_invoke + 117
6 libmono.0.dylib 0x000000010fe3b782 mono_runtime_delegate_invoke + 105
7 libmono.0.dylib 0x000000010fe62730 start_wrapper + 564
8 libmono.0.dylib 0x000000010fe92be6 thread_start_routine + 218
9 libmono.0.dylib 0x000000010feb90c2 GC_start_routine + 96
10 libsystem_pthread.dylib 0x00007fff5b2476c1 _pthread_body + 340
11 libsystem_pthread.dylib 0x00007fff5b24756d _pthread_start + 377
12 libsystem_pthread.dylib 0x00007fff5b246c5d thread_start + 13

Notes:
- Possibly a regression. Difficult to confirm, a locally built project will most likely end up without a crash.

Reproduced with:
2017.3.0p4, 2018.1.0b9, 2018.2.0a2