diff --git a/src/expert-claim/expert-claim.service.ts b/src/expert-claim/expert-claim.service.ts
index d6d9c8f..d1c3b3a 100644
--- a/src/expert-claim/expert-claim.service.ts
+++ b/src/expert-claim/expert-claim.service.ts
@@ -245,6 +245,24 @@ export class ExpertClaimService {
     return String(actor.clientKey ?? "");
   }
 
+  /**
+   * `preLockQueueSnapshot` must only store {@link ClaimWorkflowStep} values.
+   * Legacy / mistaken data sometimes put {@link ClaimCaseStatus} (e.g. WAITING_FOR_DAMAGE_EXPERT)
+   * in `workflow.currentStep`, which would fail Mongoose enum validation when snapshotted.
+   */
+  private normalizeClaimWorkflowStepForSnapshot(
+    value: unknown,
+    fallback: ClaimWorkflowStep,
+  ): ClaimWorkflowStep {
+    if (
+      typeof value === "string" &&
+      (Object.values(ClaimWorkflowStep) as string[]).includes(value)
+    ) {
+      return value as ClaimWorkflowStep;
+    }
+    return fallback;
+  }
+
   /** Owner mobile: linked blame party phone when available, else `users.mobile`. */
   private async resolveClaimOwnerPhone(claim: any): Promise<string | undefined> {
     if (!claim?.owner?.userId) return undefined;
@@ -2226,20 +2244,30 @@ export class ExpertClaimService {
       },
       'workflow.preLockQueueSnapshot': {
         claimStatus: claim.claimStatus,
-        currentStep:
-          claim.workflow?.currentStep ?? ClaimWorkflowStep.USER_SUBMISSION_COMPLETE,
+        currentStep: this.normalizeClaimWorkflowStepForSnapshot(
+          claim.workflow?.currentStep,
+          ClaimWorkflowStep.USER_SUBMISSION_COMPLETE,
+        ),
         ...(claim.workflow?.nextStep != null
-          ? { nextStep: claim.workflow.nextStep }
+          ? {
+              nextStep: this.normalizeClaimWorkflowStepForSnapshot(
+                claim.workflow.nextStep,
+                ClaimWorkflowStep.EXPERT_DAMAGE_ASSESSMENT,
+              ),
+            }
           : {}),
       },
       'workflow.currentStep': ClaimWorkflowStep.EXPERT_DAMAGE_ASSESSMENT,
       $push: {
         history: {
-          event: 'CLAIM_LOCKED',
-          performedBy: actor.sub,
-          performedByName: actor.fullName,
-          performedAt: new Date(),
-          note: `Claim locked by damage expert ${actor.fullName}`,
+          type: "CLAIM_LOCKED",
+          actor: {
+            actorId: new Types.ObjectId(actor.sub),
+            actorName: actor.fullName,
+            actorType: "damage_expert",
+          },
+          timestamp: new Date(),
+          metadata: { note: `Claim locked by damage expert ${actor.fullName}` },
         },
       },
     });
@@ -2657,11 +2685,16 @@ export class ExpertClaimService {
       }),
       $push: {
         history: {
-          event: 'IN_PERSON_VISIT_REQUESTED',
-          performedBy: actor.sub,
-          performedByName: actor.fullName,
-          performedAt: new Date(),
-          note: note || 'Expert requested in-person visit',
+          type: "IN_PERSON_VISIT_REQUESTED",
+          actor: {
+            actorId: new Types.ObjectId(actor.sub),
+            actorName: actor.fullName,
+            actorType: "damage_expert",
+          },
+          timestamp: new Date(),
+          metadata: {
+            note: note || "Expert requested in-person visit",
+          },
         },
       },
     });
@@ -2678,7 +2711,7 @@ export class ExpertClaimService {
       claimRequestId,
       status: claim.status,
       claimStatus: ClaimStatus.NEEDS_REVISION,
-      message: 'In-person visit requested. User will be notified.',
+      message: "In-person visit requested. User will be notified.",
     };
   }
 
@@ -3106,11 +3139,16 @@ export class ExpertClaimService {
       | undefined;
 
     const restoreClaimStatus = snap?.claimStatus ?? ClaimStatus.PENDING;
-    const restoreCurrent =
-      snap?.currentStep ?? ClaimWorkflowStep.USER_SUBMISSION_COMPLETE;
+    const restoreCurrent = this.normalizeClaimWorkflowStepForSnapshot(
+      snap?.currentStep,
+      ClaimWorkflowStep.USER_SUBMISSION_COMPLETE,
+    );
     const restoreNext =
       snap?.nextStep != null
-        ? snap.nextStep
+        ? this.normalizeClaimWorkflowStepForSnapshot(
+            snap.nextStep,
+            ClaimWorkflowStep.EXPERT_DAMAGE_ASSESSMENT,
+          )
         : ClaimWorkflowStep.EXPERT_DAMAGE_ASSESSMENT;
 
     const lockFieldsUnset = {
@@ -3455,42 +3493,52 @@ export class ExpertClaimService {
       : [];
     const selectedParts = body.selectedParts as string[];
 
-    if (!(claim as any).damage) (claim as any).damage = {};
-    (claim as any).damage.selectedParts = selectedParts;
+    const $set: Record<string, unknown> = {
+      "damage.selectedParts": selectedParts,
+    };
 
-    // Keep damaged-parts captures consistent with updated selection.
     const damagedPartsMedia = (claim as any).media?.damagedParts;
     if (damagedPartsMedia) {
       const selectedSet = new Set(selectedParts);
       if (damagedPartsMedia instanceof Map) {
-        for (const key of Array.from(damagedPartsMedia.keys())) {
-          if (!selectedSet.has(key)) damagedPartsMedia.delete(key);
+        const m = new Map(damagedPartsMedia as Map<string, unknown>);
+        for (const key of Array.from(m.keys())) {
+          if (!selectedSet.has(key)) m.delete(key);
         }
+        $set["media.damagedParts"] = Object.fromEntries(m.entries());
       } else {
-        for (const key of Object.keys(damagedPartsMedia)) {
-          if (!selectedSet.has(key)) delete damagedPartsMedia[key];
+        const o = {
+          ...(damagedPartsMedia as Record<string, unknown>),
+        };
+        for (const key of Object.keys(o)) {
+          if (!selectedSet.has(key)) delete o[key];
         }
+        $set["media.damagedParts"] = o;
       }
     }
 
-    if (!Array.isArray((claim as any).history)) (claim as any).history = [];
-    (claim as any).history.push({
-      event: "EXPERT_DAMAGED_PARTS_UPDATED",
-      performedBy: actor.sub,
-      performedByName: actor.fullName,
-      performedAt: new Date(),
-      note: "Damage expert edited selected damaged parts",
-      metadata: {
-        previousSelectedParts: previous,
-        selectedParts,
-        ...(damagedPartsEditSnapshot && {
-          expertProfileSnapshot: damagedPartsEditSnapshot,
-        }),
+    await this.claimCaseDbService.findByIdAndUpdate(claimRequestId, {
+      $set,
+      $push: {
+        history: {
+          type: "EXPERT_DAMAGED_PARTS_UPDATED",
+          actor: {
+            actorId: new Types.ObjectId(actor.sub),
+            actorName: actor.fullName,
+            actorType: "damage_expert",
+          },
+          timestamp: new Date(),
+          metadata: {
+            previousSelectedParts: previous,
+            selectedParts,
+            ...(damagedPartsEditSnapshot && {
+              expertProfileSnapshot: damagedPartsEditSnapshot,
+            }),
+          },
+        },
       },
     });
 
-    await (claim as any).save();
-
     return {
       claimRequestId: claim._id.toString(),
       selectedParts,