diff --git a/jaxrs-tck/src/main/java/ee/jakarta/tck/ws/rs/api/client/clientrequestcontext/JAXRSClientIT.java b/jaxrs-tck/src/main/java/ee/jakarta/tck/ws/rs/api/client/clientrequestcontext/JAXRSClientIT.java
index 6f31ef0..c246a3c 100644
--- a/jaxrs-tck/src/main/java/ee/jakarta/tck/ws/rs/api/client/clientrequestcontext/JAXRSClientIT.java
+++ b/jaxrs-tck/src/main/java/ee/jakarta/tck/ws/rs/api/client/clientrequestcontext/JAXRSClientIT.java
@@ -875,22 +875,19 @@
     ContextProvider provider = new ContextProvider() {
       @Override
       protected void checkFilterContext(ClientRequestContext context) throws Fault {
-          assertTrue(context.containsHeaderString("header1", "value"::equalsIgnoreCase));
+          assertTrue(context.containsHeaderString("header1", "value"::equals));
           assertTrue(context.containsHeaderString("HEADER1", ",", "value2"::equals));
           //Incorrect separator character
-          assertFalse(context.containsHeaderString("header1", ";", "value2"::equalsIgnoreCase));
+          assertFalse(context.containsHeaderString("header1", ";", "value2"::equals));
           //Shouldn't find first value when separator character is incorrect
-          assertFalse(context.containsHeaderString("header1", ";", "value1"::equalsIgnoreCase));
+          assertFalse(context.containsHeaderString("header1", ";", "Value1"::equalsIgnoreCase));
           //Test regular expression
-          assertTrue(context.containsHeaderString("header1", ";|,", "value2"::equalsIgnoreCase));
+          assertTrue(context.containsHeaderString("header1", ";|,", "VALUE2"::equalsIgnoreCase));
           //White space in value not trimmed
-          assertFalse(context.containsHeaderString("header1", "whitespace"::equalsIgnoreCase));
+          assertFalse(context.containsHeaderString("header1", "whitespace"::equals));
           //Multiple character separator
-          assertTrue(context.containsHeaderString("header2", "::", "Value5"::equalsIgnoreCase));
-          //Test default separator is comma
-          assertFalse(context.containsHeaderString("header3","value6"::equalsIgnoreCase));
-          String entity = "Success";
-          Response r = Response.ok(entity).build();
+          assertTrue(context.containsHeaderString("header2", ";;", "Value5"::equalsIgnoreCase));
+          Response r = Response.ok().build();
           context.abortWith(r);
       }
     };
@@ -898,13 +895,9 @@
         .header("header1", "value")
         .header("header1", "value1 , value2")
         .header("header1", "Value3,white space ")
-        .header("header2", "Value4::Value5")
-        .header("header3", "value6;value7")
+        .header("header2", "Value4;;Value5")
         .buildGet();
     Response response = invoke(invocation);
-
-    String entity = response.readEntity(String.class);
-    assertTrue(entity.contains("Success"));
   }
 
   
diff --git a/jaxrs-tck/src/main/java/ee/jakarta/tck/ws/rs/api/client/clientresponsecontext/JAXRSClientIT.java b/jaxrs-tck/src/main/java/ee/jakarta/tck/ws/rs/api/client/clientresponsecontext/JAXRSClientIT.java
index 5ab7ad8..d5afde1 100644
--- a/jaxrs-tck/src/main/java/ee/jakarta/tck/ws/rs/api/client/clientresponsecontext/JAXRSClientIT.java
+++ b/jaxrs-tck/src/main/java/ee/jakarta/tck/ws/rs/api/client/clientresponsecontext/JAXRSClientIT.java
@@ -438,38 +438,30 @@
    */
   @Test
   public void containsHeaderStringTest() throws Fault {
-      final String header1 = "Header1";
-      final String value1 = "no-store";
-      final String value2 = "{Max - Age, no-transform}";
-      final String header2 = "header2";
-      final String value3 = "{no-store;no-transform}";
       
       ContextProvider in = new ContextProvider() {
           @Override
           protected void checkFilterContext(ClientRequestContext requestContext,
                   ClientResponseContext responseContext) throws Fault {
-              assertTrue(responseContext.containsHeaderString("header1", "value"::equalsIgnoreCase));
+              assertTrue(responseContext.containsHeaderString("header1", "value"::equals));
               assertTrue(responseContext.containsHeaderString("HEADER1", ",", "value2"::equals));
               //Incorrect separator character
-              assertFalse(responseContext.containsHeaderString("header1", ";", "value2"::equalsIgnoreCase));
+              assertFalse(responseContext.containsHeaderString("header1", ";", "value2"::equals));
               //Shouldn't find first value when separator character is incorrect
-              assertFalse(responseContext.containsHeaderString("header1", ";", "value1"::equalsIgnoreCase));
+              assertFalse(responseContext.containsHeaderString("header1", ";", "Value1"::equalsIgnoreCase));
               //Test regular expression
-              assertTrue(responseContext.containsHeaderString("header1", ";|,", "value2"::equalsIgnoreCase));
+              assertTrue(responseContext.containsHeaderString("header1", ";|,", "VALUE2"::equalsIgnoreCase));
               //White space in value not trimmed
               assertFalse(responseContext.containsHeaderString("header1", "whitespace"::equalsIgnoreCase));
               //Multiple character separator
-              assertTrue(responseContext.containsHeaderString("header2", "::", "Value5"::equalsIgnoreCase));
-              //Test default separator is comma
-              assertFalse(responseContext.containsHeaderString("header3","value6"::equalsIgnoreCase));
+              assertTrue(responseContext.containsHeaderString("header2", ";;", "Value5"::equalsIgnoreCase));
           }
       };
       Response response = Response.ok()
               .header("header1", "value")
               .header("header1", "value1 , value2")
               .header("header1", "Value3,white space ")
-              .header("header2", "Value4::Value5")
-              .header("header3", "value6;value7")
+              .header("header2", "Value4;;Value5")
               .build();
       invokeWithResponseAndAssertStatus(response, Status.OK, in);
   }
diff --git a/jaxrs-tck/src/main/java/ee/jakarta/tck/ws/rs/ee/rs/core/headers/HttpHeadersTest.java b/jaxrs-tck/src/main/java/ee/jakarta/tck/ws/rs/ee/rs/core/headers/HttpHeadersTest.java
index 43a7f41..7a60b23 100644
--- a/jaxrs-tck/src/main/java/ee/jakarta/tck/ws/rs/ee/rs/core/headers/HttpHeadersTest.java
+++ b/jaxrs-tck/src/main/java/ee/jakarta/tck/ws/rs/ee/rs/core/headers/HttpHeadersTest.java
@@ -74,27 +74,32 @@
   @Path("/contains-headers")
   public String containsHeadersGet() {
     sb = new StringBuffer();
-    List<String> myHeaders = Arrays.asList("Accept", "Content-Type", "Header3");
+    sb.append("containsHeaderString= ");
 
     try {
-        assertTrue(hs.containsHeaderString("accept", "text/html"::equalsIgnoreCase));
-        sb.append("Header: accept contains text/html; ");
+        if(hs.containsHeaderString("accept", "text/html"::equals)) {
+            sb.append("Test1: accept contains text/html; ");
+        }
       
         //Verify Predicate and separator character usage
-        assertTrue(hs.containsHeaderString("Accept", ",", "Text/html;Level=1"::equalsIgnoreCase));
-        sb.append("Header: accept contains text/html;level=1; ");
+        if (hs.containsHeaderString("Accept", ",", "Text/html;Level=1"::equalsIgnoreCase)) {
+            sb.append("Test2: accept contains text/html;level=1; ");
+        }
         
         //Verify incorrect separator character fails
-        assertFalse(hs.containsHeaderString("Accept", ";", "text/html;level=1"::equals));
-        sb.append("Incorrect separator character fails as expected; ");
+        if (!(hs.containsHeaderString("Accept", ";", "text/html;level=1"::equals))) {
+            sb.append("Test3: Incorrect separator character fails as expected; ");
+        }
         
-        //Verify white space in parameter not trimmed
-        assertFalse(hs.containsHeaderString("header3", "**", "value3"::equalsIgnoreCase));
-        sb.append("White space not trimmed from parameter as expected; ");
+        //Verify white space in value not trimmed and double character separator
+        if (!(hs.containsHeaderString("header3", ";;", "value3"::equals))) {
+            sb.append("Test4: White space not trimmed from value as expected; ");
+        }
         
         //Verify white space in front and back of value trimmed
-        assertTrue(hs.containsHeaderString("HEADER3", "**", "value2"::equalsIgnoreCase));
-        sb.append("White space trimmed around value as expected; ");  
+        if (hs.containsHeaderString("HEADER3", ";;", "value2"::equalsIgnoreCase)) {
+            sb.append("Test5: White space trimmed around value as expected; ");  
+        }
     } catch (Throwable ex) {
       sb.append("Unexpected exception thrown in containsHeadersGet: "
           + ex.getMessage());
diff --git a/jaxrs-tck/src/main/java/ee/jakarta/tck/ws/rs/ee/rs/core/headers/JAXRSClientIT.java b/jaxrs-tck/src/main/java/ee/jakarta/tck/ws/rs/ee/rs/core/headers/JAXRSClientIT.java
index 1a4c8ce..bccc459 100644
--- a/jaxrs-tck/src/main/java/ee/jakarta/tck/ws/rs/ee/rs/core/headers/JAXRSClientIT.java
+++ b/jaxrs-tck/src/main/java/ee/jakarta/tck/ws/rs/ee/rs/core/headers/JAXRSClientIT.java
@@ -225,8 +225,13 @@
     setProperty(Property.REQUEST_HEADERS,
         "Content-Type:application/xml;charset=utf8");
     setProperty(Property.REQUEST_HEADERS,
-        "Header3:value1 ** value2 **value 3");
+        "Header3:value1 ;; Value2 ;;value 3");
     setProperty(Property.REQUEST, buildRequest(Request.GET, "contains-headers"));
+    setProperty(Property.SEARCH_STRING, "Test1");
+    setProperty(Property.SEARCH_STRING, "Test2");
+    setProperty(Property.SEARCH_STRING, "Test3");
+    setProperty(Property.SEARCH_STRING, "Test4");
+    setProperty(Property.SEARCH_STRING, "Test5");
     invoke();
   }