I applied a sound to trigger through the triggers settings. Seems like I got a bug or something. Could this problem appear because I started making the game in version 1.6 of the engine (not the fork), and then transferred the project to version CE 1.10.5?
Viewing post in Deleting a trigger after interacting with it?
The problem is that 1.10.5 itself is quite buggy, unfortunately. Your problem might be fixed already in latest dev build, so grab it:
https://cg8516.itch.io/easyfpseditor-ce/devlog/738937/bleeding-edge-builds