It began when google released updates for some core AndroidTV apps. The only way to solve it currently is to disable automatic updates in the Playstore app and then reboot your mibox.
Uninstall and reinstall the app.
Same issue on Mi Box 3
Same on Sony TV
i fixed mine by going to system apps and force stop and clear data for Android TV Home app.
There are few other similar threads on Reddit, I think the best one is this: https://www.reddit.com/r/MiBox/comments/dhvldw/mibox_youtube_stuck_on_update_pending/
I've tried this suggestion, without success:
Try going to Settings ---> Apps ---> Google play store ---> Clear cache and the clear data and open the play store. This will mostly likely to solve your issue.
I've tried this and it seems to work:
Uninstall updates and reinstall again. This is some google play services bug, happens sometimes.
I just uninstall the update or the app and reinstall again, that does the trick.
It's still annoying as hell, since you're probably going to lose most of customized settings you already applied to the app.
You have to enter to Google Play, My apps, and then force the update manually. Ain't it pretty but it works.
Update it
That's an issue plaguing every Android TV device, I have the Mecool KM9 Pro Classic and I'm having the same problem, you can still open apps that appear like that and if you go to the Play Store no updates are pending there. Google seems to ignore what's going on here because the problem has several weeks.
Edit: Updates to some core Android TV apps lead to this problem and it seems to be already reported to Google, a fix is coming soon...