Steps to reproduce:
1. Browse to Admin Tools -> Add Series
2. Enter a blank Series Title, fill out other fields
3. Click 'Save'
Get a "Missing or invalid input" error message that is partially correct.
Correct portion says: "Please enter a title for the series"
Misleading error says: "The title you have entered is already used by another series"
There should be no mention of an already used series title, only the first error message
Workaround (if any):
Enter a valid series title