Unable to Create a Revenue Recognition Journal Entry as Location is Mandatory but the Location Preference is Already Turned Off

The Setup > Accounting > Accounting Preferences, General > Classifications > Make Location Mandatory is already unchecked. A user is still getting an error when creating Revenue Recognition Journal Entries. 

There might be a Custom Line Field for Location causing this error. 

1. Go to Customization > Lists, Records, & Fields > Transaction Line Fields.
2. Check the list in case the user has a custom field for Location. 
3. At Validation & Defaulting subtab, checkbox Mandatory might be checked. If it is checked, uncheck it.
4. Click Save.