Steps to reproduce

1. Click Create Issue.
2. Choose "Configure Fields", select "Where is my field?".
3. Select a field.

Result

You'll immediately get a "The JIRA server was contacted but has returned an error response. We are unsure of the result of this operation."

The Javascript console reports this:

[Error] Failed to load resource: https://<instance>/rest/whereismycf/1.0/fields/creator the server responded with a status of 400 (Bad Request)

The content of that request:

Either 'issueKey', or 'projectKey' or 'projectId' parameter must be provided in the request

This appears to only happen in the Create Issue screen, it works fine when viewing an already-existing issue.