We aren’t able to reproduce the issue on our test Dashboards.
Can you try temporarily deactivating all non-MainWP plugins on the Dashboard site, then open the Dashboard in an incognito/private browser window and see if that helps?
I’m delighted to hear that you’ve identified the cause of the issue with MainWP’s Update Overview. It seems like an inadvertent change to the setting for a Staging site has been causing some confusion. Thank you for rectifying this.
To ensure your Update Overview reflects the correct numbers, please navigate to Site > Updates and use the filter on the right to set your site as a Production site. This can also be visualised through the link you provided: MainWP Overview Notification Display Issue Changing the filter from Staging to Production will display the update numbers accurately.