Swagger UI not working when Spring controller uses parameter Map - spring-mvc

Question

We are using Swagger and Spring Fox version 2.5.0, POM entry below. When we create a Spring MVC controller that has uses a parameter Map (see example below), then the Swagger-UI page does not properly generate. The controller in question does not appear on the Swagger-UI page and none of the controllers that come after it appear also (in alphabetical order).
#RequestMapping(value = "/resource/", method = RequestMethod.GET, produces = {"application/json"})
public void get(#RequestParam MultiValueMap<String, String> params) {
//code
}
When the params Map is removed, then everything is fine. Any idea what the issue could be or how to get around it?
Below is more info that may or may not be useful.
the dependencies:
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger2</artifactId>
<version>2.5.0</version>
</dependency>
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger-ui</artifactId>
<version>2.5.0</version>
</dependency>
the Swagger config:
#Configuration
#EnableSwagger2
public class SwaggerConfiguration {
#Bean
public Docket api() {
Docket docket = new Docket(DocumentationType.SWAGGER_2)
.apiInfo(apiInfo())
.select()
.paths(PathSelectors.any())
.build();
docket.ignoredParameterTypes(Principal.class);
return docket;
}
private ApiInfo apiInfo() {
return new ApiInfoBuilder().title("some app")
.description("some description")
.build();
}
}