unconditionally adding the folder

conan/internal/api/profile/profile_loader.py

@@ -123,12 +123,9 @@ def _load_profile(self, profile_name, cwd):
                    "conan_version": conan_version,
                    "detect_api": detect_api}
 
-        # If the profile is in the home profiles folder, use the profiles folder as search
-        # path too, to allow loading "common" profiles in common folders, not only children
-        loader_paths = base_path
-        if os.path.commonpath([profiles_folder]) == os.path.commonpath([profiles_folder,
-                                                                        profile_path]):
-            loader_paths = [base_path, profiles_folder]
+        # Always include the root Conan home "profiles" folder as secondary route for loading
+        # imports and includes from jinja2 templates.
+        loader_paths = [base_path, profiles_folder]
         rtemplate = Environment(loader=FileSystemLoader(loader_paths)).from_string(text)
 
         try:

test/integration/configuration/test_profile_jinja.py

@@ -108,6 +108,24 @@ def test_profile_template_include_sibling():
     assert "os=FreeBSD" in client.out
 
 
+def test_profile_template_include_from_cache():
+    # https://github.com/conan-io/conan/issues/17431
+    client = TestClient()
+    tpl1 = textwrap.dedent(r"""
+        {% include "sub2/profile_vars" %}
+        """)
+    tpl2 = textwrap.dedent("""
+        {% set a = "FreeBSD" %}
+        [settings]
+        os = {{ a }}
+        """)
+    client.save_home({"profiles/sub2/profile_vars": tpl2})
+    client.save({"conanfile.py": GenConanfile(),
+                 "sub1/profile1": tpl1})
+    client.run("install . -pr=sub1/profile1")
+    assert "os=FreeBSD" in client.out
+
+
 def test_profile_template_profile_dir():
     client = TestClient()
     tpl1 = textwrap.dedent("""