diff --git a/models/issues/comment.go b/models/issues/comment.go
index 69d43f16d1..de0d2fd0f4 100644
--- a/models/issues/comment.go
+++ b/models/issues/comment.go
@@ -277,6 +277,15 @@ func NewProjectWorkflowDoer(title string, workflowID int64, workflowEvent projec
 	}
 }
 
+// IsProjectWorkflowDoer reports whether the doer is the virtual project workflow actor.
+func IsProjectWorkflowDoer(doer *user_model.User) bool {
+	if doer == nil {
+		return false
+	}
+	_, ok := doer.ExtDoerData.(*projectWorkflowDoer)
+	return ok
+}
+
 // Comment represents a comment in commit and issue page.
 type Comment struct {
 	ID               int64            `xorm:"pk autoincr"`
diff --git a/models/issues/comment_meta_test.go b/models/issues/comment_meta_test.go
index 59e139382d..9f2351f895 100644
--- a/models/issues/comment_meta_test.go
+++ b/models/issues/comment_meta_test.go
@@ -67,4 +67,7 @@ func TestBuildCreateCommentMetaData(t *testing.T) {
 	}
 	meta = buildCreateCommentMetaData(&CreateCommentOptions{Doer: nilMetaDoer})
 	assert.Nil(t, meta, "value-type projectWorkflowDoer must not match *projectWorkflowDoer type assertion")
+	assert.True(t, IsProjectWorkflowDoer(workflowDoer))
+	assert.False(t, IsProjectWorkflowDoer(nilMetaDoer))
+	assert.False(t, IsProjectWorkflowDoer(&user_model.User{ID: 1}))
 }
diff --git a/services/projects/workflow_notifier.go b/services/projects/workflow_notifier.go
index cb1f623ca7..77486ef208 100644
--- a/services/projects/workflow_notifier.go
+++ b/services/projects/workflow_notifier.go
@@ -73,7 +73,7 @@ func (m *workflowNotifier) NewPullRequest(ctx context.Context, pr *issues_model.
 func (m *workflowNotifier) IssueChangeStatus(ctx context.Context, doer *user_model.User, commitID string, issue *issues_model.Issue, actionComment *issues_model.Comment, isClosed bool) {
 	// Skip state changes triggered by workflow actions to prevent cascade loops
 	// (same guard as feed/notifier.go).
-	if doer.ExtDoerData != nil {
+	if issues_model.IsProjectWorkflowDoer(doer) {
 		return
 	}
 	if err := issue.LoadRepo(ctx); err != nil {
@@ -106,6 +106,9 @@ func (m *workflowNotifier) IssueChangeStatus(ctx context.Context, doer *user_mod
 }
 
 func (*workflowNotifier) IssueChangeProjects(ctx context.Context, doer *user_model.User, issue *issues_model.Issue, oldProjectColumnMap map[int64]int64, newProjects []*project_model.Project) {
+	if issues_model.IsProjectWorkflowDoer(doer) {
+		return
+	}
 	addedProjects := make(map[int64]*project_model.Project)
 	for _, newProject := range newProjects {
 		// Use key presence check; column ID 0 is technically valid.
@@ -166,7 +169,7 @@ func (*workflowNotifier) IssueChangeProjects(ctx context.Context, doer *user_mod
 
 func (*workflowNotifier) IssueChangeProjectColumn(ctx context.Context, doer *user_model.User, issue *issues_model.Issue, oldColumnID, newColumnID int64) {
 	// Skip column moves triggered by workflow actions to prevent cascade loops.
-	if doer.ExtDoerData != nil {
+	if issues_model.IsProjectWorkflowDoer(doer) {
 		return
 	}
 	if err := issue.LoadRepo(ctx); err != nil {
@@ -219,6 +222,9 @@ func (*workflowNotifier) IssueChangeProjectColumn(ctx context.Context, doer *use
 }
 
 func (*workflowNotifier) MergePullRequest(ctx context.Context, doer *user_model.User, pr *issues_model.PullRequest) {
+	if issues_model.IsProjectWorkflowDoer(doer) {
+		return
+	}
 	if err := pr.LoadIssue(ctx); err != nil {
 		log.Error("MergePullRequest: LoadIssue: %v", err)
 		return
@@ -255,6 +261,9 @@ func (*workflowNotifier) MergePullRequest(ctx context.Context, doer *user_model.
 }
 
 func (m *workflowNotifier) AutoMergePullRequest(ctx context.Context, doer *user_model.User, pr *issues_model.PullRequest) {
+	if issues_model.IsProjectWorkflowDoer(doer) {
+		return
+	}
 	m.MergePullRequest(ctx, doer, pr)
 }