flasgger 0.9.7.1 does not refer some $ref elements

[rhee519]

In some cases, flasgger 0.9.7.1 does not refer some $ref elements, with no error.
For the test, I just modified the flasgger version(v0.9.71 <-> v0.9.5) in requirements.txt and reloaded the api server.

v0.9.5

SwaggerUI displays the correct example responses.

v0.9.7.1

Some $ref appears as raw string instead of actual reference.

Setting

Here's the part of my swagger.config.json.