diff --git a/oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/oidc/web/logout/OidcClientInitiatedLogoutSuccessHandler.java b/oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/oidc/web/logout/OidcClientInitiatedLogoutSuccessHandler.java
index ca1993d7ddb..275d485638e 100644
--- a/oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/oidc/web/logout/OidcClientInitiatedLogoutSuccessHandler.java
+++ b/oauth2/oauth2-client/src/main/java/org/springframework/security/oauth2/client/oidc/web/logout/OidcClientInitiatedLogoutSuccessHandler.java
@@ -63,7 +63,7 @@ protected String determineTargetUrl(HttpServletRequest request,
 			endSessionEndpoint = this.endSessionEndpoint(clientRegistration);
 			if (endSessionEndpoint != null) {
 				String idToken = idToken(authentication);
-				URI postLogoutRedirectUri = postLogoutRedirectUri(request);
+				String postLogoutRedirectUri = postLogoutRedirectUri(request);
 				targetUrl = endpointUri(endSessionEndpoint, idToken, postLogoutRedirectUri);
 			}
 		}
@@ -91,7 +91,7 @@ private String idToken(Authentication authentication) {
 		return ((OidcUser) authentication.getPrincipal()).getIdToken().getTokenValue();
 	}
 
-	private URI postLogoutRedirectUri(HttpServletRequest request) {
+	private String postLogoutRedirectUri(HttpServletRequest request) {
 		if (this.postLogoutRedirectUri == null) {
 			return null;
 		}
@@ -100,13 +100,12 @@ private URI postLogoutRedirectUri(HttpServletRequest request) {
 				.replaceQuery(null)
 				.fragment(null)
 				.build();
-		return URI.create (UriComponentsBuilder.fromUriString(this.postLogoutRedirectUri)
+		return UriComponentsBuilder.fromUriString(this.postLogoutRedirectUri)
 				.buildAndExpand(Collections.singletonMap("baseUrl", uriComponents.toUriString()))
-				.toUriString());
+				.toUriString();
 	}
 
-
-	private String endpointUri(URI endSessionEndpoint, String idToken, URI postLogoutRedirectUri) {
+	private String endpointUri(URI endSessionEndpoint, String idToken, String postLogoutRedirectUri) {
 		UriComponentsBuilder builder = UriComponentsBuilder.fromUri(endSessionEndpoint);
 		builder.queryParam("id_token_hint", idToken);
 		if (postLogoutRedirectUri != null) {
diff --git a/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/oidc/web/logout/OidcClientInitiatedLogoutSuccessHandlerTests.java b/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/oidc/web/logout/OidcClientInitiatedLogoutSuccessHandlerTests.java
index 023959f4687..7a7a6b82b99 100644
--- a/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/oidc/web/logout/OidcClientInitiatedLogoutSuccessHandlerTests.java
+++ b/oauth2/oauth2-client/src/test/java/org/springframework/security/oauth2/client/oidc/web/logout/OidcClientInitiatedLogoutSuccessHandlerTests.java
@@ -165,15 +165,17 @@ public void logoutWhenUsingPostLogoutRedirectUriTemplateThenBuildsItForRedirect(
 				"post_logout_redirect_uri=https://rp.example.org");
 	}
 
+	// gh-9511
 	@Test
-	public void logoutWhenUsingPostLogoutRedirectUriWithQueryParametersThenBuildItForRedirectWithEncodedQueryParameters() throws IOException, ServletException {
+	public void logoutWhenUsingPostLogoutRedirectUriWithQueryParametersThenBuildsItForRedirect()
+			throws IOException, ServletException {
 		OAuth2AuthenticationToken token = new OAuth2AuthenticationToken(TestOidcUsers.create(),
 				AuthorityUtils.NO_AUTHORITIES, this.registration.getRegistrationId());
 		this.handler.setPostLogoutRedirectUri("https://rp.example.org/context?forwardUrl=secured%3Fparam%3Dtrue");
 		this.request.setUserPrincipal(token);
 		this.handler.onLogoutSuccess(this.request, this.response, token);
-		assertThat(this.response.getRedirectedUrl()).isEqualTo(
-				"https://endpoint?" + "id_token_hint=id-token&" + "post_logout_redirect_uri=https://rp.example.org/context?forwardUrl%3Dsecured%253Fparam%253Dtrue");
+		assertThat(this.response.getRedirectedUrl()).isEqualTo("https://endpoint?id_token_hint=id-token&"
+				+ "post_logout_redirect_uri=https://rp.example.org/context?forwardUrl%3Dsecured%253Fparam%253Dtrue");
 	}
 
 	@Test