Checklist

• I have verified that that issue exists against the master branch of Django REST framework.
• I have searched for similar issues in both open and closed tickets and cannot find a duplicate.
• This is not a usage question. (Those should be directed to the discussion group instead.)
• This cannot be dealt with as a third party library. (We prefer new functionality to be in the form of third party libraries where possible.)
• I have reduced the issue to the simplest possible case.
• I have included a failing test as a pull request. (If you are unable to do so we can still accept the issue.)

Steps to reproduce

1. Create a JSONField on a serializer
2. Submit {"a": "test"} to the field through docs
3. Breakpoint at the return of JSONField.to_internal_value()

Expected behavior

The returned data is a dictionary with a single key a that has a value which is string test.

Actual behavior

The returned data is the string {"a": "test"}