From what I can see it looks like a compatibility issue more than anything, especially considering the "Credits" command is actually opening the Chapter Select scene. To start I would put the plugin at the bottom of the plugin list in your plugin manager, however if this does not work and chances are it won't then you will have to disable any plugin that changes the title scene and it's commands. Doing this should help you figure out which plugin is causing the problem, you may even have to disable all other plugins and slowly enable them all one by one.