diff --git a/build_test.go b/build_test.go
index 2e7f58c..78a46c4 100644
--- a/build_test.go
+++ b/build_test.go
@@ -475,7 +475,7 @@ func TestBuildSourceEligibilitySurvivesLaterCheckoutCleanup(t *testing.T) {
 import("fmt";"os";"gitea.maximumdirect.net/eric/ReleaseKit/buildinfo")
 func main(){ if len(os.Args)>1 && os.Args[1]=="version" {fmt.Println("fixture",buildinfo.Version())} }
 `
-	for _, mode := range []string{"clean", "dirty before build", "changed during build"} {
+	for _, mode := range []string{"clean", "dirty before build", "changed during build", "commit during build"} {
 		t.Run(mode, func(t *testing.T) {
 			repository := newBuildConsumer(t, source)
 			writeBuildFixture(t, repository, "docs/releases/v1.2.3.md", "# Fixture v1.2.3\n")
@@ -488,8 +488,14 @@ func main(){ if len(os.Args)>1 && os.Args[1]=="version" {fmt.Println("fixture",b
 			}
 			var writer *sourceChangeWriter
 			request := releasekit.BuildRequest{RepositoryDir: repository, Version: "v1.2.3", Spec: releasekit.BuildSpec{MainPackage: "./cmd/app", BinaryName: "fixture", Targets: []releasekit.Target{{OS: runtime.GOOS, Arch: runtime.GOARCH}}}, OutputDir: t.TempDir()}
-			if mode == "changed during build" {
-				writer = &sourceChangeWriter{change: mutate}
+			if mode == "changed during build" || mode == "commit during build" {
+				writer = &sourceChangeWriter{change: func() {
+					mutate()
+					if mode == "commit during build" {
+						buildGit(t, repository, "add", "--all")
+						buildGit(t, repository, "commit", "-m", "source advanced during compilation")
+					}
+				}}
 				request.Output = writer
 			}
 			result, err := releasekit.Build(context.Background(), request)
@@ -503,6 +509,7 @@ func main(){ if len(os.Args)>1 && os.Args[1]=="version" {fmt.Println("fixture",b
 				return
 			}
 			buildGit(t, repository, "restore", "cmd/app/main.go")
+			buildGit(t, repository, "checkout", "--detach", "v1.2.3")
 			delivered, err := releasekit.Deliver(context.Background(), releasekit.DeliveryRequest{RepositoryDir: repository, Product: "Fixture", Version: "v1.2.3", Build: &result})
 			if err == nil || !strings.Contains(err.Error(), "build source") || delivered.State != releasekit.DeliveryNotAttempted {
 				t.Fatalf("dirty source delivered: %#v %v", delivered, err)
diff --git a/docs/roadmap/remediation.md b/docs/roadmap/remediation.md
index c41cabb..e98e05e 100644
--- a/docs/roadmap/remediation.md
+++ b/docs/roadmap/remediation.md
@@ -91,7 +91,8 @@ the supported API and CLI receipt path.
 set only after completed builds observe clean source and unchanged HEAD. Local
 dirty builds remain supported; binary delivery rejects their results and
 receipts even after checkout cleanup. API tests cover clean, initially dirty,
-and changed-during-build source; a CLI regression covers receipt delivery after
+changed-during-build source, and HEAD advancement; a CLI regression covers
+receipt delivery after
 cleanup. The offline suite and public boundary checks pass.
 
 ### R2 — High: Some successful page writes are reported as not attempted