Reproduction steps:
1. Open the attached project with macOS machine.
2. Make sure Scripting Runtime Version is set to .NET 4.6 in Player settings.
3. Play the Crash scene.
4. Wait for "done" is logged in the Console.
5. Stop the scene.
6. Play the scene.
- Editor crashes.

0 libmonobdwgc-2.0.dylib mono_handle_native_crash + 277
1 libsystem_platform.dylib _sigtramp + 26
2 ??? 0x0 + 0
3 libsystem_c.dylib abort + 129
4 libmonobdwgc-2.0.dylib mono_log_write_logfile + 336
5 libmonobdwgc-2.0.dylib monoeg_g_logv + 83
6 libmonobdwgc-2.0.dylib monoeg_g_log + 134
7 libmonobdwgc-2.0.dylib wait_for_tids + 260
8 libmonobdwgc-2.0.dylib mono_threads_abort_appdomain_threads + 160
9 libmonobdwgc-2.0.dylib unload_thread_main + 182
10 libmonobdwgc-2.0.dylib inner_start_thread + 128
11 libmonobdwgc-2.0.dylib GC_inner_start_routine + 90
12 libmonobdwgc-2.0.dylib GC_start_routine + 28
13 libsystem_pthread.dylib _pthread_body + 180
14 libsystem_pthread.dylib _pthread_body + 0
15 libsystem_pthread.dylib thread_start + 13

Reproduced with:
2017.1.0b1, 2017.3.0b1
.NET4.6

Not reproducible with:
.NET 3.5