diff --git a/awx/main/tasks/jobs.py b/awx/main/tasks/jobs.py
index c441e6ce1a..1b47de4f45 100644
--- a/awx/main/tasks/jobs.py
+++ b/awx/main/tasks/jobs.py
@@ -885,7 +885,9 @@ class SourceControlMixin(BaseTask):
         # Determine whether or not this project sync needs to populate the cache for Ansible content, roles and collections
         has_cache = os.path.exists(os.path.join(project.get_cache_path(), project.cache_id))
         # Galaxy requirements are not supported for manual projects
-        if project.scm_type and ((not has_cache) or branch_override):
+        # If a source update is scheduled, always include roles/collections because
+        # the new revision may have different requirements.
+        if project.scm_type and ((not has_cache) or branch_override or source_update_tag in sync_needs):
             sync_needs.extend(['install_roles', 'install_collections'])
 
         return sync_needs
diff --git a/awx/main/tests/unit/tasks/test_jobs.py b/awx/main/tests/unit/tasks/test_jobs.py
index 0fc0fa98b6..ffe99cb2f6 100644
--- a/awx/main/tests/unit/tasks/test_jobs.py
+++ b/awx/main/tests/unit/tasks/test_jobs.py
@@ -1,4 +1,5 @@
 # -*- coding: utf-8 -*-
+import os
 import pytest
 from unittest import mock
 
@@ -661,3 +662,82 @@ class TestRunInventoryUpdatePopulateWorkloadIdentityTokens:
 
         # The instance's get_cloud_credential should now return the same object with context
         assert task.instance.get_cloud_credential() is cloud_cred
+
+
+class TestGetSyncNeeds:
+    """Tests for SourceControlMixin.get_sync_needs cache behavior."""
+
+    def _make_task_and_project(self, tmp_path, scm_revision='abc123', local_head='abc123', cache_exists=True):
+        """Create a SourceControlMixin instance and a mock project for testing get_sync_needs."""
+        project_path = str(tmp_path / 'project')
+        os.makedirs(project_path, exist_ok=True)
+
+        cache_base = str(tmp_path / 'cache')
+        os.makedirs(cache_base, exist_ok=True)
+        if cache_exists and scm_revision:
+            os.makedirs(os.path.join(cache_base, scm_revision), exist_ok=True)
+
+        project = mock.MagicMock()
+        project.scm_type = 'git'
+        project.scm_revision = scm_revision
+        project.scm_branch = 'main'
+        project.get_project_path.return_value = project_path
+        project.get_cache_path.return_value = cache_base
+        project.cache_id = scm_revision if scm_revision else 'fallback'
+
+        git_repo = mock.MagicMock()
+        git_repo.head.commit.hexsha = local_head
+
+        task = jobs.SourceControlMixin()
+        task.instance = mock.MagicMock(spec=Job)
+
+        return task, project, git_repo
+
+    def test_source_update_forces_role_install(self, tmp_path):
+        """When a source update is needed (local HEAD differs from project revision),
+        install_roles and install_collections must be included even if cache exists.
+        A new revision may have changed requirements.yml."""
+        task, project, git_repo = self._make_task_and_project(
+            tmp_path,
+            scm_revision='abc123',
+            local_head='def456',
+            cache_exists=True,
+        )
+
+        with mock.patch('awx.main.tasks.jobs.git.Repo', return_value=git_repo):
+            sync_needs = task.get_sync_needs(project)
+
+        assert 'update_git' in sync_needs
+        assert 'install_roles' in sync_needs
+        assert 'install_collections' in sync_needs
+
+    def test_no_sync_when_revision_matches_and_cache_exists(self, tmp_path):
+        """When local HEAD matches project revision and cache exists, no sync needed."""
+        task, project, git_repo = self._make_task_and_project(
+            tmp_path,
+            scm_revision='abc123',
+            local_head='abc123',
+            cache_exists=True,
+        )
+
+        with mock.patch('awx.main.tasks.jobs.git.Repo', return_value=git_repo):
+            sync_needs = task.get_sync_needs(project)
+
+        assert sync_needs == []
+
+    def test_cache_miss_triggers_role_install(self, tmp_path):
+        """When cache doesn't exist, install_roles and install_collections are needed
+        even if the git revision matches."""
+        task, project, git_repo = self._make_task_and_project(
+            tmp_path,
+            scm_revision='abc123',
+            local_head='abc123',
+            cache_exists=False,
+        )
+
+        with mock.patch('awx.main.tasks.jobs.git.Repo', return_value=git_repo):
+            sync_needs = task.get_sync_needs(project)
+
+        assert 'update_git' not in sync_needs
+        assert 'install_roles' in sync_needs
+        assert 'install_collections' in sync_needs