Error and 404 response using X-Forwarded headers with an async api

Hi,

Using :

• a spring-boot-webflux application
• behind a proxy that sends X-Forwarded headers
• with undertow servlet

I get :

• an IllegalArgumentException (viewable in debug mode only)
• my call gets a 30 seconds delay before the following response
  • {"timestamp":"2022-02-15T14:51:51.363+00:00","status":404,"error":"Not Found","path":"/api/rest/\{ "testAsync": "Hello foo"}

    "}