Import Open API v2 Doc in HTTP service > DF removes definitions

I’m facing to an error during doc import for an HTTP service
Doc is a JSON Open API v2 and it’s working fine as swaggerUI from API service provider
But when I create service and import doc, DreamFactory convert it to Open API v3 and remove all definitions

If I convert doc to Open API v3 before importing it, definitions are implemented.

Is it a bug from DF?
Version = 4.5.3