diff --git a/json-path/src/main/java/com/jayway/jsonpath/internal/path/PathCompiler.java b/json-path/src/main/java/com/jayway/jsonpath/internal/path/PathCompiler.java
index a118f9ca4..14d950f10 100644
--- a/json-path/src/main/java/com/jayway/jsonpath/internal/path/PathCompiler.java
+++ b/json-path/src/main/java/com/jayway/jsonpath/internal/path/PathCompiler.java
@@ -333,7 +333,8 @@ else if (isPathContext(c)) {
                 // we've encountered a COMMA do the same
                 case CLOSE_PARENTHESIS:
                     groupParen--;
-                    if (0 != groupParen) {
+                    //CS304 Issue link: https://github.com/json-path/JsonPath/issues/620
+                    if (0 > groupParen ) {
                         parameter.append(c);
                     }
                 case COMMA:
diff --git a/json-path/src/test/java/com/jayway/jsonpath/old/IssuesTest.java b/json-path/src/test/java/com/jayway/jsonpath/old/IssuesTest.java
index 3bf7f1d38..cf7583f18 100644
--- a/json-path/src/test/java/com/jayway/jsonpath/old/IssuesTest.java
+++ b/json-path/src/test/java/com/jayway/jsonpath/old/IssuesTest.java
@@ -1021,7 +1021,7 @@ public void issue_309(){
         assertThat((String)doc.read("$.jsonArr[0].name")).isEqualTo("nOne");
         assertThat((String)doc.read("$.jsonArr[1].name")).isEqualTo("Jayway");
     }
-    
+
     @Test
     public void issue_378(){
 
@@ -1039,7 +1039,7 @@ public void issue_378(){
             .jsonProvider(new JacksonJsonNodeJsonProvider())
             .mappingProvider(new JacksonMappingProvider())
             .build();
-        
+
         DocumentContext ctx = JsonPath.using(configuration).parse(json);
 
         String path = "$.nodes[*][?(!([\"1.2.3.4\"] subsetof @.ntpServers))].ntpServers";
@@ -1047,4 +1047,73 @@ public void issue_378(){
 
         ctx.read(jsonPath);
     }
+
+    //CS304 (manually written) Issue link: https://github.com/json-path/JsonPath/issues/620
+    @Test
+    public void issue_620_1(){
+        String json = "{\n" +
+                "  \"complexText\": {\n" +
+                "    \"nestedFields\": [\n" +
+                "      {\n" +
+                "        \"index\": \"0\",\n" +
+                "        \"name\": \"A\"\n" +
+                "      },\n" +
+                "      {\n" +
+                "        \"index\": \"1\",\n" +
+                "        \"name\": \"B\"\n" +
+                "      },\n" +
+                "      {\n" +
+                "        \"index\": \"2\",\n" +
+                "        \"name\": \"C\"\n" +
+                "      }\n" +
+                "    ]\n" +
+                "  }\n" +
+                "}";
+
+        String path1 = "$.concat($.complexText.nestedFields[?(@.index == '2')].name," +
+                "$.complexText.nestedFields[?(@.index == '1')].name," +
+                "$.complexText.nestedFields[?(@.index == '0')].name)";
+        String path2 = "$.concat($.complexText.nestedFields[2].name," +
+                "$.complexText.nestedFields[1].name," +
+                "$.complexText.nestedFields[0].name)";
+
+        assertThat((String)JsonPath.read(json,path1)).isEqualTo("CBA");
+        assertThat((String)JsonPath.read(json,path2)).isEqualTo("CBA");
+    }
+    //CS304 (manually written) Issue link: https://github.com/json-path/JsonPath/issues/620
+    @Test
+    public void issue_620_2(){
+        String json = "{\n" +
+                "  \"complexText\": {\n" +
+                "    \"nestedFields\": [\n" +
+                "      {\n" +
+                "        \"index\": \"0\",\n" +
+                "        \"name\": \"A\"\n" +
+                "      },\n" +
+                "      {\n" +
+                "        \"index\": \"1\",\n" +
+                "        \"name\": \"B\"\n" +
+                "      },\n" +
+                "      {\n" +
+                "        \"index\": \"2\",\n" +
+                "        \"name\": \"C\"\n" +
+                "      }\n" +
+                "    ]\n" +
+                "  }\n" +
+                "}";
+
+        String path1 = "$.concat($.complexText.nestedFields[?(@.index == '2')].name," +
+                "$.complexText.nestedFields[?((@.index == '1')].name," +
+                "$.complexText.nestedFields[?(@.index == '0')].name)";
+
+        boolean thrown = false;
+
+        try {
+            Object result = (Object) JsonPath.read(json,path1);
+        } catch (Exception e) {
+            thrown = true;
+        }
+
+        assertTrue(thrown);
+    }
 }