diff --git a/crates/scanner/src/scanner_io.rs b/crates/scanner/src/scanner_io.rs
index 887cc3d79..d1cc7a073 100644
--- a/crates/scanner/src/scanner_io.rs
+++ b/crates/scanner/src/scanner_io.rs
@@ -183,6 +183,18 @@ fn complete_scanner_cache_baseline_plan_digest(proof: ScannerCacheBaselineProof<
         return None;
     }
 
+    // Completed maintenance also covers ordinary usage. Keep its exact stored
+    // proof for cache reuse, and reject mixtures of different set work proofs.
+    let baseline_plan_digest = DataUsageScanPlanDigest(baseline.usage_snapshot_set_states.first()?.scan_plan_digest?);
+    if ![
+        proof.scan_plan_digest,
+        scanner_bucket_work_digest(proof.scan_plan_digest, HealScanMode::Normal, true),
+        scanner_bucket_work_digest(proof.scan_plan_digest, HealScanMode::Deep, true),
+    ]
+    .contains(&baseline_plan_digest)
+    {
+        return None;
+    }
     let mut states = HashSet::with_capacity(baseline.usage_snapshot_set_states.len());
     for state in &baseline.usage_snapshot_set_states {
         let source = DataUsageCacheSource::new(usize::try_from(state.pool_index).ok()?, usize::try_from(state.set_index).ok()?);
@@ -192,13 +204,13 @@ fn complete_scanner_cache_baseline_plan_digest(proof: ScannerCacheBaselineProof<
             || state.tombstone
             || state.scanner_epoch != Some(proof.leader_epoch)
             || state.scanner_cycle.is_none_or(|cycle| cycle > proof.want_cycle)
-            || state.scan_plan_digest != Some(proof.scan_plan_digest.0)
+            || state.scan_plan_digest != Some(baseline_plan_digest.0)
         {
             return None;
         }
     }
 
-    (states == *proof.expected_sources).then_some(proof.scan_plan_digest)
+    (states == *proof.expected_sources).then_some(baseline_plan_digest)
 }
 
 fn scoped_scan_scope_from_dirty_buckets(
diff --git a/crates/scanner/src/scanner_io/io_cache.rs b/crates/scanner/src/scanner_io/io_cache.rs
index fb141d517..4289d1efd 100644
--- a/crates/scanner/src/scanner_io/io_cache.rs
+++ b/crates/scanner/src/scanner_io/io_cache.rs
@@ -126,6 +126,7 @@ impl ScannerIOCache for SetDisks {
             cache_cycle_floor,
         } = scan_plan;
         let bucket_work_digest = scanner_bucket_work_digest(bucket_coverage_digest, scan_mode, requires_full_scan);
+        let scan_plan_digest = scanner_bucket_work_digest(scan_plan_digest, scan_mode, requires_full_scan);
         let pool_label = self.pool_index.to_string();
         let set_label = self.set_index.to_string();
 
diff --git a/crates/scanner/src/scanner_io/io_cycle.rs b/crates/scanner/src/scanner_io/io_cycle.rs
index b06ccc8d4..1d3ce57b5 100644
--- a/crates/scanner/src/scanner_io/io_cycle.rs
+++ b/crates/scanner/src/scanner_io/io_cycle.rs
@@ -275,10 +275,11 @@ where
     }
     bucket_plan_complete &= buckets_by_source.keys().copied().collect::<HashSet<_>>() == *expected_sources;
     bucket_plan_complete &= scanner_bucket_inventory_is_complete(&all_buckets, &buckets_by_source);
-    let scan_plan_digest =
+    let structural_scan_plan_digest =
         scanner_bucket_plan_digest(&all_buckets, crate::scanner::scanner_activity_structural_digest(&activity_before));
     let bucket_coverage_digest =
         scanner_bucket_plan_digest(&all_buckets, crate::scanner::scanner_activity_snapshot_digest(&activity_before));
+    let scan_plan_digest = scanner_bucket_work_digest(structural_scan_plan_digest, scan_mode, requires_full_scan);
     let dirty_usage_snapshot = Arc::new(snapshot_dirty_usage_buckets(&all_buckets, dirty_generation_before_bucket_list));
     let scan_scope = resolve_scanner_bucket_scan_scope(
         store,
@@ -290,7 +291,7 @@ where
                 expected_sources: &expected_sources,
                 leader_epoch,
                 want_cycle,
-                scan_plan_digest,
+                scan_plan_digest: structural_scan_plan_digest,
             },
             activity_before: &activity_before,
             dirty_usage_snapshot: &dirty_usage_snapshot,
@@ -431,7 +432,7 @@ where
             buckets: set_buckets,
             all_buckets: Arc::clone(&all_buckets),
             scope: scan_scope.clone(),
-            digest: scan_plan_digest,
+            digest: structural_scan_plan_digest,
             bucket_coverage_digest,
             requires_full_scan,
             leader_epoch,
diff --git a/crates/scanner/src/scanner_io/tests.rs b/crates/scanner/src/scanner_io/tests.rs
index 66a908bd2..0391c4928 100644
--- a/crates/scanner/src/scanner_io/tests.rs
+++ b/crates/scanner/src/scanner_io/tests.rs
@@ -1137,6 +1137,36 @@ fn scoped_scan_selects_only_current_dirty_buckets_after_baseline_validation() {
     assert_ne!(scope.baseline_scan_plan_digest, Some(baseline_scan_plan_digest));
 }
 
+#[test]
+fn scoped_scan_baseline_work_proof_requires_uniform_known_set_identity() {
+    let source = DataUsageCacheSource::new(1, 2);
+    let second_source = DataUsageCacheSource::new(1, 3);
+    let sources = HashSet::from([source, second_source]);
+    let structural = DataUsageScanPlanDigest([9; 32]);
+    let full = scanner_bucket_work_digest(structural, HealScanMode::Normal, true);
+    let deep = scanner_bucket_work_digest(structural, HealScanMode::Deep, true);
+    let encoded = complete_usage_baseline(source, full, 7, 11);
+    let baseline: DataUsageInfo = serde_json::from_slice(&encoded).expect("baseline should decode");
+    for (second_plan, expected) in [(full, Some(full)), (deep, None), (DataUsageScanPlanDigest([8; 32]), None)] {
+        let mut candidate = baseline.clone();
+        let mut second = candidate.usage_snapshot_set_states[0].clone();
+        second.set_index = 3;
+        second.scan_plan_digest = Some(second_plan.0);
+        candidate.usage_snapshot_set_states.push(second);
+        let data = Bytes::from(serde_json::to_vec(&candidate).expect("candidate should encode"));
+        assert_eq!(
+            complete_scanner_cache_baseline_plan_digest(ScannerCacheBaselineProof {
+                data: Some(&data),
+                expected_sources: &sources,
+                leader_epoch: 11,
+                want_cycle: 8,
+                scan_plan_digest: structural,
+            }),
+            expected
+        );
+    }
+}
+
 fn peer_dirty_usage_snapshot(
     instance_id: &str,
     generation: u64,