[CI4] Toolbar DB Query And Event Duplication

You are modifying the core Events class, which on subsequent CI updates your changes will unfortunately be overridden. I think you hit the jackpot there but instead of modifying the check on events discovery, you should check instead if the file to be included is not the same app file in app/Config/Events.php . I think you should open an issue ticket in the Github repo to properly address this.