diff --git a/json-path/src/main/java/com/jayway/jsonpath/internal/filter/FilterCompiler.java b/json-path/src/main/java/com/jayway/jsonpath/internal/filter/FilterCompiler.java
index ecec37091..828350f8b 100644
--- a/json-path/src/main/java/com/jayway/jsonpath/internal/filter/FilterCompiler.java
+++ b/json-path/src/main/java/com/jayway/jsonpath/internal/filter/FilterCompiler.java
@@ -355,6 +355,7 @@ private PathNode readPath() {
         int begin = filter.position();
 
         filter.incrementPosition(1); //skip $ and @
+        int groupParen = 0;
         while (filter.inBounds()) {
             if (filter.currentChar() == OPEN_SQUARE_BRACKET) {
                 int closingSquareBracketIndex = filter.indexOfMatchingCloseChar(filter.position(), OPEN_SQUARE_BRACKET, CLOSE_SQUARE_BRACKET, true, false);
@@ -364,14 +365,31 @@ private PathNode readPath() {
                     filter.setPosition(closingSquareBracketIndex + 1);
                 }
             }
-            boolean closingFunctionBracket = (filter.currentChar() == CLOSE_PARENTHESIS && currentCharIsClosingFunctionBracket(begin));
-            boolean closingLogicalBracket  = (filter.currentChar() == CLOSE_PARENTHESIS && !closingFunctionBracket);
 
-            if (!filter.inBounds() || isRelationalOperatorChar(filter.currentChar()) || filter.currentChar() == SPACE || closingLogicalBracket) {
-                break;
+            if (filter.currentChar() == OPEN_PARENTHESIS) {
+                groupParen++;
+            }
+
+            if (groupParen == 0) {
+                boolean closingFunctionBracket = (filter.currentChar() == CLOSE_PARENTHESIS && currentCharIsClosingFunctionBracket(begin));
+                boolean closingLogicalBracket  = (filter.currentChar() == CLOSE_PARENTHESIS && !closingFunctionBracket);
+
+                if (!filter.inBounds() || isRelationalOperatorChar(filter.currentChar()) || filter.currentChar() == SPACE || closingLogicalBracket) {
+                    break;
+                } else {
+                    filter.incrementPosition(1);
+                }
             } else {
+                if (filter.currentChar() == CLOSE_PARENTHESIS) {
+                    groupParen--;
+                    if (groupParen < 0) {
+                        throw new InvalidPathException("Parentheses does not match in filter " + filter);
+                    }
+                }
                 filter.incrementPosition(1);
             }
+
+
         }
 
         boolean shouldExists = !(previousSignificantChar == NOT);
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 27b6e0633..40e75c28d 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
@@ -349,15 +349,11 @@ else if (isPathContext(c)) {
                 // we've encountered a COMMA do the same
                 case CLOSE_PARENTHESIS:
                     groupParen--;
-                    //CS304 Issue link: https://github.com/json-path/JsonPath/issues/620
-                    if (0 > groupParen || priorChar == '(') {
-                        parameter.append(c);
-                    }
                 case COMMA:
                     // In this state we've reach the end of a function parameter and we can pass along the parameter string
                     // to the parser
                     if ((0 == groupQuote && 0 == groupBrace && 0 == groupBracket
-                            && ((0 == groupParen && CLOSE_PARENTHESIS == c) || 1 == groupParen))) {
+                            && ((0 == groupParen && CLOSE_PARENTHESIS == c) || (1 == groupParen && c == COMMA)))) {
                         endOfStream = (0 == groupParen);
 
                         if (null != type) {
diff --git a/json-path/src/test/java/com/jayway/jsonpath/InlineFilterTest.java b/json-path/src/test/java/com/jayway/jsonpath/InlineFilterTest.java
index 1249474a6..7dcd5fc9b 100644
--- a/json-path/src/test/java/com/jayway/jsonpath/InlineFilterTest.java
+++ b/json-path/src/test/java/com/jayway/jsonpath/InlineFilterTest.java
@@ -286,4 +286,11 @@ public void escape_pattern_before_literal(Configuration conf) {
     public void filter_evaluation_does_not_break_path_evaluation(Configuration conf) {
         assertHasOneResult("[{\"s\": \"fo\", \"expected_size\": \"m\"}, {\"s\": \"lo\", \"expected_size\": 2}]", "$[?(@.s size @.expected_size)]", conf);
     }
+
+    @ParameterizedTest
+    @MethodSource("configurations")
+    public void testFilterCallingFunction(Configuration conf) {
+        assertHasOneResult("[[\"abcdef\"]]", "$[?(@.concat(\"-\") == \"abcdef-\")]", conf);
+    }
+
 }
diff --git a/json-path/src/test/java/com/jayway/jsonpath/internal/function/NestedFunctionTest.java b/json-path/src/test/java/com/jayway/jsonpath/internal/function/NestedFunctionTest.java
index 36faf6563..0b7695bc8 100644
--- a/json-path/src/test/java/com/jayway/jsonpath/internal/function/NestedFunctionTest.java
+++ b/json-path/src/test/java/com/jayway/jsonpath/internal/function/NestedFunctionTest.java
@@ -73,6 +73,14 @@ public void testStringConcat(Configuration conf) {
     }
 
 
+    @ParameterizedTest
+    @MethodSource("configurations")
+    public void testMultipleCall(Configuration conf) {
+        verifyTextFunction(conf, "$.concat($.text[0], $.concat( $.concat($.text[3], \"-1\"), $.concat($.text[4], \"-1\")))", "ad-1e-1");
+    }
+
+
+
     @ParameterizedTest
     @MethodSource("configurations")
     public void testStringAndNumberConcat(Configuration conf) {