EventManager#unregisterListeners unregisters the plugin main instance

@Plugin(
    id = "testplugin"
)
public class TestPlugin {
  @Inject
  private ProxyServer server;

  @Subscribe
  public void onProxyInitialization(ProxyInitializeEvent event) {
    EventManager eventManager = this.server.getEventManager();
    eventManager.unregisterListeners(this);
    System.out.println("test123");
  }

  @Subscribe
  public void onProxyReload(ProxyReloadEvent event) {
    System.out.println("test321");
  }
}

Excepted behaviour:

• It writes test123 on startup
• It writes test321 after /velocity reload

Current behaviour:

• It writes test123 on startup
• It doesn't write test321 after /velocity reload

We can't register the main instance again (eventManager.registerListeners(this, this)) as the "The plugin main instance is automatically registered." error appears