One way to add items to Zotero from the results page of EMU's Esearch database (Esearch box is toward center of library home page) is to click the folder icon in your browser's address bar
BEFORE clicking the folder icon, ALWAYS refresh/reload the browser page
How do you refresh/reload the browser page?
Click the browser's Refresh/Reload Page button
Or use Keyboard Commands: F5
or Ctrl + R (Windows/Linux) / Cmd + R (Mac)