Why does 'Upload' disappear from modern document library?

Bruno Aleixo Yes, I just checked and it's fixed now - at least on the 2 libraries that were having problems.. Thank you MS!

And sorry for not answering your questions - just got back online. I was going to come in this morning and test to see if it was the bug I heard about where paging seemed to be broken. But these were standard libraries, no customizations besides adding simple fields, no custom buttons... and the idea of why a web part would work and not the actual view seemed plausible.

I had a user experience the same issue this morning around 6:30 am EST. After a reboot of her computer the upload button did reappear. I do see the message in Message Center of the incident but no update that it's fixed. How do we know that it's been fixed since the incident says that it is intermittent and doesn't happen on all libraries?