Software 'button' keeps appearing on log in screen even after updates are completed.
Hi and welcome to the Forum.
Can you tell us which version and flavour of ZorinOS you are using e.g. Zorin16 Core, Pro or maybe Zorin 15.3 Lite?
Can you please attach a screenshot of the unexpected Software "button" that you mention.
According to websearch I have just done, it is gnome Software and Updates Notification issue. There was a bug indicating available software updates when there are none, but that should have been fixed long ago.
Do you have your Software and Updates pointing to "Main Server" as reccommended, or is it pointing to a local country server?
I don't know if this item will be of use: