Those presets were made long before this Play-Test Applet was a thing. What I meant in my last comment was that I recreated the setup and rules of Yangsi in the Play-Test Applet, clicked Start Position, clicked Game Code to get the code, and edited the Yangsi preset to make a fake preset using that code. After that, I tested the fake preset, and after moving a piece, the error showed up.
Those presets were made long before this Play-Test Applet was a thing. What I meant in my last comment was that I recreated the setup and rules of Yangsi in the Play-Test Applet, clicked Start Position, clicked Game Code to get the code, and edited the Yangsi preset to make a fake preset using that code. After that, I tested the fake preset, and after moving a piece, the error showed up.