problem with URL encoding

trying to run a request with

/demo/get?timeZone=%2B02%3A00

causes proxied service to fail with because parameter is received as ' 02:00' instead of '+02:00'

my simple gateway config:

 @Bean
    public RouterFunction<ServerResponse> demoRoute() {
        return route("demo")
                .route(path("/demo/**"), http("http://localhost:8080/demo/"))
                .before(preserveHostHeader())
                .build();
    }

Start by reproducing the demoRoute request with the encoded +02:00 value and inspect the proxied request received by the downstream service. Trace URL handling through the gateway route and add or update coverage for this case; done means the downstream parameter remains '+02:00' rather than becoming ' 02:00'.