Spring-boot logout with logoutSuccessHandler not clearing JSESSIONID cookie

Question

I'm using spring boot with a custom logout success handler. I want to print a custom message on the login screen depending on why they were logged out.

@Component
public class LogoutSuccessHandler extends SimpleUrlLogoutSuccessHandler {

    @Override
    public void onLogoutSuccess(HttpServletRequest request, HttpServletResponse response, Authentication authentication) throws IOException, ServletException {

        if(request.getParameter("emailchange") != null) {
            setDefaultTargetUrl("/signin?m=Your%20email%20address%20has%20been%20changed,%20please%20re-login.");
        }
        else if(request.getParameter("passwordchange") != null) {
            setDefaultTargetUrl("/signin?m=Your%20password%20has%20been%20changed,%20please%20re-login.");
        }
        else {
            setDefaultTargetUrl("/signin?m=You%20have%20been%20logged%20out.");
        }

        super.onLogoutSuccess(request, response, authentication);
    }

}

My security is configured as follows:

@Override
protected void configure(HttpSecurity http) throws Exception {

    http
        .authorizeRequests()
            .antMatchers("/admin/**").hasRole("ADMIN")
            .anyRequest().authenticated()
            .and()
        .formLogin()
            .loginPage("/signin")
            .loginProcessingUrl("/signin/authenticate")
            .failureUrl("/signin?login_error=t")
            .defaultSuccessUrl("/dashboard")
            .permitAll()
            .and()
        .logout()
            .logoutUrl("/signout")
            .logoutSuccessHandler(logoutSuccessHandler)
            .deleteCookies("JSESSIONID")
            .permitAll()
            .and()
        .sessionManagement()
            .sessionCreationPolicy(SessionCreationPolicy.IF_REQUIRED)
            .sessionAuthenticationStrategy(new RegisterSessionAuthenticationStrategy(sessionRegistry))
            .and()
        .rememberMe()
            .key("myrememberkey")
            .rememberMeServices(rememberMeServices)
            .and()
        .requestCache()
            .requestCache(requestCache)
            .and()
        .httpBasic()
            .disable()
        ;
}

<form id="logout-form" action="<c:url value="/signout"/>" method="POST"><input type="hidden" name="${_csrf.parameterName}" value="${_csrf.token}"/><a href="#" onclick="document.getElementById('logout-form').submit();"><i class="fa fa-power-off"></i>&nbsp;Logout</a></form>

When I logout with a POST (I'm using csrf), my LogoutSuccessHandler is called, and the JSESSIONID cookie header shows that it should be deleted. This comes back as a 302 redirect with the correct url that was set from LogoutSuccessHandler.

The browser then attempts to load /signin?m=You%20have%20been%20logged%20out but it re-sends the OLD cookie that was supposedly deleted in the 302 response from POST /signout. This causes another re-direct (since the JSESSION cookie we sent has been invalidated) and then we lose my pretty message. Any ideas on how I can prevent this behavior or ensure the browser deletes cookies properly on a 302 redirect in response to a POST request? I've tested on the latest Firefox and Chrome and the behavior is the same.