diff --git a/frontend/src/components/ui/treatment/TreatmentWorkspace.tsx b/frontend/src/components/ui/treatment/TreatmentWorkspace.tsx
index dd659c9..ce4ac0d 100644
--- a/frontend/src/components/ui/treatment/TreatmentWorkspace.tsx
+++ b/frontend/src/components/ui/treatment/TreatmentWorkspace.tsx
@@ -551,6 +551,13 @@ export function TreatmentWorkspace({
   const draftHydratingRef = useRef(false);
   const workspaceModeRef = useRef(workspaceMode);
   workspaceModeRef.current = workspaceMode;
+  /**
+   * `persistDraft` prunes a lab-dependent detail down to the teeth its jobs cover, and it reads
+   * this ref — not React state. So any handler that changes the drafts and then saves in the
+   * same tick must write the ref beside `setLabCaseDrafts`; the render-time assignment below has
+   * not run yet. Skipping it saves the detail with no teeth, and the lab-case request that
+   * follows is then rejected with TREATMENT_TOOTH_NOT_ON_DETAIL.
+   */
   const labCaseDraftsRef = useRef(labCaseDrafts);
   labCaseDraftsRef.current = labCaseDrafts;
   const skipNextGetDraftRef = useRef(false);
@@ -2278,6 +2285,7 @@ export function TreatmentWorkspace({
           }));
         });
         const updatedLabCases = [...labCaseDrafts, draft];
+        labCaseDraftsRef.current = updatedLabCases;
         setLabCaseDrafts(updatedLabCases);
 
         // Persist the new detail first so lab-case rows can use real treatmentDetailIds.
@@ -2432,6 +2440,7 @@ export function TreatmentWorkspace({
       const updatedLabCases = cleaned.map((lc) =>
         lc.clientId === orphan.clientId ? { ...lc, detailClientId: activeDetailId } : lc,
       );
+      labCaseDraftsRef.current = updatedLabCases;
       setLabCaseDrafts(updatedLabCases);
       setActiveLabCaseId(orphan.clientId);
 
@@ -2450,6 +2459,7 @@ export function TreatmentWorkspace({
       attachmentIds: activeDetail?.attachmentMetas.map((a) => a.id) ?? [],
     };
     const updatedLabCases = [...cleaned, next];
+    labCaseDraftsRef.current = updatedLabCases;
     setLabCaseDrafts(updatedLabCases);
     setActiveLabCaseId(next.clientId);