diff --git a/HISTORY.rst b/HISTORY.rst
index 2add298a..650412d3 100644
--- a/HISTORY.rst
+++ b/HISTORY.rst
@@ -42,6 +42,7 @@ PlatformIO 3.0
 
 * Fixed "systemd-udevd" warnings in `99-platformio-udev.rules <http://docs.platformio.org/en/latest/faq.html#platformio-udev-rules>`__ (`issue #2442 <https://github.com/platformio/platformio-core/issues/2442>`_)
 * Fixed an issue when ``-U`` in ``build_flags`` does not remove macro previously defined via ``-D`` flag (`issue #2508 <https://github.com/platformio/platformio-core/issues/2508>`_)
+* Fixed an issue for Project Generator when include path search order is inconsistent to what passed to the compiler (`issue #2509 <https://github.com/platformio/platformio-core/issues/2509>`_)
 
 3.6.7 (2019-04-23)
 ~~~~~~~~~~~~~~~~~~
diff --git a/platformio/builder/main.py b/platformio/builder/main.py
index 4ccbd0f9..4604fc9c 100644
--- a/platformio/builder/main.py
+++ b/platformio/builder/main.py
@@ -26,6 +26,7 @@ from SCons.Script import AllowSubstExceptions  # pylint: disable=import-error
 from SCons.Script import AlwaysBuild  # pylint: disable=import-error
 from SCons.Script import Default  # pylint: disable=import-error
 from SCons.Script import DefaultEnvironment  # pylint: disable=import-error
+from SCons.Script import Import  # pylint: disable=import-error
 from SCons.Script import Variables  # pylint: disable=import-error
 
 from platformio import util
@@ -216,8 +217,11 @@ if "envdump" in COMMAND_LINE_TARGETS:
 
 if "idedata" in COMMAND_LINE_TARGETS:
     try:
+        Import("projenv")
         print("\n%s\n" % path_to_unicode(
-            json.dumps(env.DumpIDEData(), ensure_ascii=False)))
+            json.dumps(
+                env.DumpIDEData(projenv),  # pylint: disable=undefined-variable
+                ensure_ascii=False)))
         env.Exit(0)
     except UnicodeDecodeError:
         sys.stderr.write(
diff --git a/platformio/builder/tools/pioide.py b/platformio/builder/tools/pioide.py
index c6d8fbc0..8efcd60d 100644
--- a/platformio/builder/tools/pioide.py
+++ b/platformio/builder/tools/pioide.py
@@ -26,11 +26,11 @@ from platformio.managers.core import get_core_package_dir
 from platformio.proc import exec_command
 
 
-def _dump_includes(env):
+def _dump_includes(env, projenv):
     includes = []
 
-    for item in env.get("CPPPATH", []):
-        includes.append(env.subst(item))
+    for item in projenv.get("CPPPATH", []):
+        includes.append(projenv.subst(item))
 
     # installed libs
     for lb in env.GetLibBuilders():
@@ -135,7 +135,7 @@ def _get_svd_path(env):
     return None
 
 
-def DumpIDEData(env):
+def DumpIDEData(env, projenv):
     LINTCCOM = "$CFLAGS $CCFLAGS $CPPFLAGS"
     LINTCXXCOM = "$CXXFLAGS $CCFLAGS $CPPFLAGS"
 
@@ -145,7 +145,7 @@ def DumpIDEData(env):
         "defines":
         _dump_defines(env),
         "includes":
-        _dump_includes(env),
+        _dump_includes(env, projenv),
         "cc_flags":
         env.subst(LINTCCOM),
         "cxx_flags":
diff --git a/platformio/builder/tools/piolib.py b/platformio/builder/tools/piolib.py
index a132c379..b63dd0f9 100644
--- a/platformio/builder/tools/piolib.py
+++ b/platformio/builder/tools/piolib.py
@@ -832,7 +832,9 @@ class ProjectAsLibBuilder(LibBuilderBase):
         project_include_dir = self.env.subst("$PROJECTINCLUDE_DIR")
         if isdir(project_include_dir):
             include_dirs.append(project_include_dir)
-        include_dirs.extend(LibBuilderBase.get_include_dirs(self))
+        for include_dir in LibBuilderBase.get_include_dirs(self):
+            if include_dir not in include_dirs:
+                include_dirs.append(include_dir)
         return include_dirs
 
     def get_search_files(self):