For readers of this topic, I was able to narrow down the issue further, and it turns out that this is not a bug with the extension/demo itself, but rather a bug with GameMaker. I just tried the extension in a different game engine, a GameMaker clone called STIGMA, I maintain, (my fork of ENIGMA), and it doesn't crash on any platform, not even on Windows. Since both STIGMA and GameMaker rely on identical code for the xProcess extension, this is how we know it is a bug with GameMaker and not my extension. You can download the EXE made with STIGMA yourself if you would like to see for yourself what I am talking about:
https://github.com/time-killer-games/ENIGMA-StockfishChess-Demo/releases/downloa... You will notice if you leave the EXE running for a long time (it has the depth set to 1,000) it won't ever crash. I am going to report this bug to YoYoGames, but it is so specific to my extension and doesn't really effect any other projects, I doubt they will fix it, so no one should hold their breath or be the least bit hopeful about this. Previous download link includes a Windows EXE, macOS APP. Linux ELF, and not to mention there is also the GM81 project file which may be edited and compiled with STIGMA. STIGMA can be downloaded here: https://samuel-venable.itch.io/stigma-development-environment