Please update your IWP admin panel to the latest versions 2.15.5.4.1 and 3.1.8.1.
Upon updating, click Reload data on your admin panel and go to the Activity log page immediately.
Here click the icon as shown in the screenshot below to stop any pending update tasks.
Now, try updating the plugins/themes/core/translation on your WordPress sites via the IWP admin panel.
Feel free to contact us if you need any additional information or assistance further.