Steps to reproduce:
1. Create a Series with the title "NEW SERIES"
2. Open "Add Event" dialog
3. Left-click on "Add Event->Metadata->Series"
The just created series "NEW SERIES" does not show up in the Series dropdown selection list
The just created series "NEW SERIES" should show up.
Workaround (if any):
Reloading the page solves the problem
This will likely also effect the Series dropdown selection list used to filter Series.
Cannot reproduce this anyone, it can remember, however, that this was a problem until recently. It most likely has been fixed as part of PR 627.