If a plugin couldn't be started during the DefaultPluginManagers init() phase, we try to disable it (com.atlassian.plugin.DefaultPluginManager.addPlugins(PluginLoader, Collection<Plugin>)). For a TriggerModuleDescriptor this will cause a call to com.atlassian.confluence.plugin.descriptor.TriggerModuleDescriptor.disabled(), which then tries to get the corresponding module from a JobModuleDescriptor of that plugin which might not be loaded at that time, causing an ISE at com.atlassian.confluence.plugin.module.PluginModuleHolder.getModule().