diff --git a/pageserver/src/tenant/timeline/compaction.rs b/pageserver/src/tenant/timeline/compaction.rs
index 42b36f7252..123079804b 100644
--- a/pageserver/src/tenant/timeline/compaction.rs
+++ b/pageserver/src/tenant/timeline/compaction.rs
@@ -1091,7 +1091,7 @@ impl Timeline {
         let latest_gc_cutoff = self.get_applied_gc_cutoff_lsn();
 
         tracing::info!(
-            "latest_gc_cutoff: {}, pitr cutoff {}",
+            "starting shard ancestor compaction, latest_gc_cutoff: {}, pitr cutoff {}",
             *latest_gc_cutoff,
             self.gc_info.read().unwrap().cutoffs.time
         );
@@ -1120,6 +1120,7 @@ impl Timeline {
                     // Expensive, exhaustive check of keys in this layer: this guards against ShardedRange's calculations being
                     // wrong.  If ShardedRange claims the local page count is zero, then no keys in this layer
                     // should be !is_key_disposable()
+                    // TODO: exclude sparse keyspace from this check, otherwise it will infinitely loop.
                     let range = layer_desc.get_key_range();
                     let mut key = range.start;
                     while key < range.end {
diff --git a/storage_scrubber/src/pageserver_physical_gc.rs b/storage_scrubber/src/pageserver_physical_gc.rs
index c956b1abbc..f14341c7bc 100644
--- a/storage_scrubber/src/pageserver_physical_gc.rs
+++ b/storage_scrubber/src/pageserver_physical_gc.rs
@@ -152,10 +152,8 @@ impl TenantRefAccumulator {
             }
         }
 
-        if !ancestor_refs.is_empty() {
-            tracing::info!(%ttid, "Found {} ancestor refs", ancestor_refs.len());
-            self.ancestor_ref_shards.update(ttid, ancestor_refs);
-        }
+        tracing::info!(%ttid, "Found {} ancestor refs", ancestor_refs.len());
+        self.ancestor_ref_shards.update(ttid, ancestor_refs);
     }
 
     /// Consume Self and return a vector of ancestor tenant shards that should be GC'd, and map of referenced ancestor layers to preserve
@@ -779,7 +777,7 @@ pub async fn pageserver_physical_gc(
 
     let mut summary = GcSummary::default();
     {
-        let timelines = std::pin::pin!(timelines.try_buffered(CONCURRENCY));
+        let timelines = timelines.try_buffered(CONCURRENCY);
         let timelines = timelines.try_flatten();
 
         let timelines = timelines.map_ok(|(ttid, tenant_manifest_arc)| {
@@ -793,8 +791,8 @@ pub async fn pageserver_physical_gc(
                 tenant_manifest_arc,
             )
         });
-        let mut timelines = std::pin::pin!(timelines.try_buffered(CONCURRENCY));
-
+        let timelines = timelines.try_buffered(CONCURRENCY);
+        let mut timelines = std::pin::pin!(timelines);
         // Drain futures for per-shard GC, populating accumulator as a side effect
         while let Some(i) = timelines.next().await {
             summary.merge(i?);