diff --git a/chasm/lib/activity/frontend.go b/chasm/lib/activity/frontend.go
index c013b17c245..eb738455b22 100644
--- a/chasm/lib/activity/frontend.go
+++ b/chasm/lib/activity/frontend.go
@@ -294,8 +294,6 @@ func (h *frontendHandler) TerminateActivityExecution(
 	}
 
 	if req.GetRequestId() == "" {
-		// Since this mutates the request, we clone it first so that any retries use the original request.
-		req = common.CloneProto(req)
 		req.RequestId = uuid.NewString()
 	}
 
@@ -333,8 +331,6 @@ func (h *frontendHandler) RequestCancelActivityExecution(
 	}
 
 	if req.GetRequestId() == "" {
-		// Since this mutates the request, we clone it first so that any retries use the original request.
-		req = common.CloneProto(req)
 		req.RequestId = uuid.NewString()
 	}
 
@@ -362,6 +358,9 @@ func (h *frontendHandler) validateAndPopulateStartRequest(
 	req *workflowservice.StartActivityExecutionRequest,
 	namespaceID namespace.ID,
 ) (*workflowservice.StartActivityExecutionRequest, error) {
+	if req.GetRequestId() == "" {
+		req.RequestId = uuid.NewString()
+	}
 	// Since validation includes mutation of the request, we clone it first so that any retries use the original request.
 	req = common.CloneProto(req)
 	activityType := req.ActivityType.GetName()
@@ -400,10 +399,6 @@ func (h *frontendHandler) validateAndPopulateStartRequest(
 func (h *frontendHandler) validateAndNormalizeStartActivityExecutionRequest(
 	req *workflowservice.StartActivityExecutionRequest,
 ) error {
-	if req.GetRequestId() == "" {
-		req.RequestId = uuid.NewString()
-	}
-
 	maxIDLengthLimit := h.config.MaxIDLengthLimit()
 
 	if len(req.GetRequestId()) > maxIDLengthLimit {
diff --git a/chasm/lib/activity/frontend_test.go b/chasm/lib/activity/frontend_test.go
new file mode 100644
index 00000000000..9607e7d6869
--- /dev/null
+++ b/chasm/lib/activity/frontend_test.go
@@ -0,0 +1,65 @@
+package activity
+
+import (
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+	commonpb "go.temporal.io/api/common/v1"
+	taskqueuepb "go.temporal.io/api/taskqueue/v1"
+	"go.temporal.io/api/workflowservice/v1"
+	"go.temporal.io/server/common/log"
+	"go.temporal.io/server/common/namespace"
+	"google.golang.org/protobuf/types/known/durationpb"
+)
+
+// TestRequestIdStableAcrossRetries verifies that a request ID is re-used
+// across retries, even if server-generated.
+func TestRequestIdStableAcrossRetries(t *testing.T) {
+	h := &frontendHandler{
+		config: &Config{
+			BlobSizeLimitError:         defaultBlobSizeLimitError,
+			BlobSizeLimitWarn:          defaultBlobSizeLimitWarn,
+			MaxIDLengthLimit:           func() int { return defaultMaxIDLengthLimit },
+			DefaultActivityRetryPolicy: getDefaultRetrySettings,
+		},
+		logger: log.NewNoopLogger(),
+	}
+	nsID := namespace.ID("test-namespace-id")
+
+	newReq := func(requestId string) *workflowservice.StartActivityExecutionRequest {
+		return &workflowservice.StartActivityExecutionRequest{
+			Namespace:  "test-namespace",
+			ActivityId: "test-activity",
+			ActivityType: &commonpb.ActivityType{
+				Name: "test-type",
+			},
+			TaskQueue: &taskqueuepb.TaskQueue{
+				Name: "test-queue",
+			},
+			StartToCloseTimeout: durationpb.New(time.Minute),
+			RequestId:           requestId,
+		}
+	}
+
+	// Simulate two RetryableInterceptor attempts: both call
+	// validateAndPopulateStartRequest with the same request pointer.
+	validateTwoAttempts := func(t *testing.T, req *workflowservice.StartActivityExecutionRequest) {
+		t.Helper()
+		clone1, err := h.validateAndPopulateStartRequest(req, nsID)
+		require.NoError(t, err)
+		require.NotEmpty(t, clone1.RequestId)
+
+		clone2, err := h.validateAndPopulateStartRequest(req, nsID)
+		require.NoError(t, err)
+		require.Equal(t, clone1.RequestId, clone2.RequestId)
+	}
+
+	t.Run("server-generated", func(t *testing.T) {
+		validateTwoAttempts(t, newReq(""))
+	})
+
+	t.Run("client-provided", func(t *testing.T) {
+		validateTwoAttempts(t, newReq("my-request-id"))
+	})
+}