diff --git a/spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/support/ServerWebExchangeUtils.java b/spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/support/ServerWebExchangeUtils.java
index 678591ff..68ce8223 100644
--- a/spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/support/ServerWebExchangeUtils.java
+++ b/spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/support/ServerWebExchangeUtils.java
@@ -208,13 +208,16 @@ public final class ServerWebExchangeUtils {
 		boolean encoded = (uri.getRawQuery() != null && uri.getRawQuery().contains("%"))
 				|| (uri.getRawPath() != null && uri.getRawPath().contains("%"));
 
-		// Verify if it is really fully encoded. Treat partial encoded as uncoded.
+		// Verify if it is really fully encoded. Treat partial encoded as unencoded.
 		if (encoded) {
 			try {
 				UriComponentsBuilder.fromUri(uri).build(true);
 				return true;
 			}
 			catch (IllegalArgumentException ignore) {
+				if (log.isTraceEnabled()) {
+					log.trace("Error in containsEncodedParts", ignore);
+				}
 			}
 
 			return false;
diff --git a/spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/filter/RouteToRequestUrlFilterTests.java b/spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/filter/RouteToRequestUrlFilterTests.java
index 2224e11f..a63f0bdc 100644
--- a/spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/filter/RouteToRequestUrlFilterTests.java
+++ b/spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/filter/RouteToRequestUrlFilterTests.java
@@ -18,7 +18,6 @@ package org.springframework.cloud.gateway.filter;
 
 import java.net.URI;
 
-import org.junit.Ignore;
 import org.junit.Test;
 import org.mockito.ArgumentCaptor;
 import reactor.core.publisher.Mono;
@@ -116,7 +115,6 @@ public class RouteToRequestUrlFilterTests {
 	}
 
 	@Test
-	@Ignore // FIXME: gh-1551
 	public void partialEncodedParameters() {
 		URI url = UriComponentsBuilder
 				.fromUriString("http://localhost/get?key[]=test= key&start=1533108081")
@@ -134,10 +132,12 @@ public class RouteToRequestUrlFilterTests {
 		ServerWebExchange webExchange = testFilter(request, "http://myhost");
 		URI uri = webExchange.getRequiredAttribute(GATEWAY_REQUEST_URL_ATTR);
 		assertThat(uri).hasScheme("http").hasHost("myhost")
-				.hasParameter("key[]", "test= key").hasParameter("start", "1533108081");
+				// since https://github.com/joel-costigliola/assertj-core/issues/1699
+				// assertj uses raw query
+				.hasParameter("key[]", "test=%20key").hasParameter("start", "1533108081");
 
 		// prove that it is double encoded since partial encoded uri is treated as
-		// uncoded.
+		// unencoded.
 		assertThat(uri.getRawQuery()).isEqualTo("key[]=test=%2520key&start=1533108081");
 	}