Reproduction steps:
1. Download the necessary files from "Project.zip"
2. Create a folder on your drive "<your local path>\CoreClient"
3. Unzip the following files in that directory, each should create their own subdirectory

• CoreClientGameTemplate.zip
• GameClient.zip
• StaticData.zip

4. In the command prompt window, navigate to "\CoreClient\CoreClientGameTemplate\DotNetTools"
5. Run 'webfileserver --root "<local path to>\CoreClient\GameClient\Build" --port 57470 --enable-cors'
6. Open the project "CoreClientGameTemplate"
7. Go to the top-left menu item "Turbine Tools->Test->Unity Freeze->Test Thrasher"
8. Click the "Start" button on the "Thrasher" WIndow
9. Let the process run until the Editor crashes

Expected result: the Editor does not crash
Actual result: the Editor crashes

Reproduces on: 2018.4.24f1, 2019.4.26f1, 2020.3.7f1, 2021.1.7f1, 2021.2.0a16
Does not reproduce on: 2018.4.23f1

First 10 lines of Stacktrace:
ono-2.0-bdwgc) [c:\build\output\unity-technologies\mono\mono\metadata\threads.c:4055] mono_thread_get_undeniable_exception
ERROR: SymGetSymFromAddr64, GetLastError: 'The specified module could not be found.' (Address: 00000000189E25DF)
ERROR: SymGetModuleInfo64, GetLastError: 'A dynamic link library (DLL) initialization routine failed.' (Address: 00000000189E25DF)
0x00000000189E25DF ((<unknown>)) (function-name not available)
0x000000003E296D33 (Mono JIT Code) System.Net.Sockets.Socket/<>c:<.cctor>b__309_11 (System.IOAsyncResult)
0x000000003CB28AF8 (Mono JIT Code) System.IOSelectorJob:System.Threading.IThreadPoolWorkItem.ExecuteWorkItem ()
0x000000003B24EFE5 (Mono JIT Code) System.Threading.ThreadPoolWorkQueue:Dispatch ()
0x000000003B24E123 (Mono JIT Code) System.Threading._ThreadPoolWaitCallback:PerformWaitCallback ()
0x00000000135B8AE5 (Mono JIT Code) (wrapper runtime-invoke) <Module>:runtime_invoke_bool (object,intptr,intptr,intptr)
0x00007FF9DC4BB900 (mono-2.0-bdwgc) [c:\build\output\unity-technologies\mono\mono\mini\mini-runtime.c:2809] mono_jit_runtime_invoke

Notes:
-The issue might manifest as a crash or a freeze, however, the callstacks seem to be the same