Spring webflux doesn't populate custom object from path variables with @ModelAttribute

I'm trying to adapt an application that works well with Spring MVC but that has a different behavior with Spring WebFlux

Here's my code with Spring Boot 5 - Spring MVC :

The controller :

@RestController
public class MyRestController {

    @GetMapping("/test/{id}/{label}")
    public ResponseEntity<Payload> test(@ModelAttribute Payload payload) {
        return new ResponseEntity<>(payload,HttpStatus.OK);
    }
}

The Payload object :

public class Payload {

    @NotNull
    private int id;

    private String label;

    public Payload() {}

    public String getLabel() {
        return label;
    }

    public void setLabel(String label) {
        this.label = label;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }
}

My pom.xml

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.0.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
</dependencies>

I don't have written any custom converter, Spring populate my payload object automatically, everything is fine.

When I call :

http://localhost:8080/test/25/helloWorld

Response is

{"id":25,"label":"helloWorld"}

Then, I only change my pom.xml, switching from web to webflux :

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.1.0.RELEASE</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-webflux</artifactId>
    </dependency>
</dependencies>

And my Payload Object isn't populated anymore.

When I call :

http://localhost:8080/test/25/helloWorld

Response is

{"id":0,"label":null}

I know I could write a converter and register it with @ControllerAdvice, but I can't imagine that there isn't an automated solution to make it works again as it has always worked with Spring Web.

Does anyone already encountered the same problem as me ?

Thanks,

Julien