diff --git a/pgxn/neon/libpagestore.c b/pgxn/neon/libpagestore.c
index acb8092990..caffdc9612 100644
--- a/pgxn/neon/libpagestore.c
+++ b/pgxn/neon/libpagestore.c
@@ -178,6 +178,8 @@ static PageServer page_servers[MAX_SHARDS];
 static bool pageserver_flush(shardno_t shard_no);
 static void pageserver_disconnect(shardno_t shard_no);
 static void pageserver_disconnect_shard(shardno_t shard_no);
+// HADRON
+shardno_t get_num_shards(void);
 
 static bool
 PagestoreShmemIsValid(void)
@@ -286,6 +288,22 @@ AssignPageserverConnstring(const char *newval, void *extra)
 	}
 }
 
+/* BEGIN_HADRON */
+/**
+ * Return the total number of shards seen in the shard map.
+ */
+shardno_t get_num_shards(void)
+{
+	const ShardMap *shard_map;
+
+	Assert(pagestore_shared);
+	shard_map = &pagestore_shared->shard_map;
+
+	Assert(shard_map != NULL);
+	return shard_map->num_shards;
+}
+/* END_HADRON */
+
 /*
  * Get the current number of shards, and/or the connection string for a
  * particular shard from the shard map in shared memory.
diff --git a/pgxn/neon/walproposer_pg.c b/pgxn/neon/walproposer_pg.c
index 93807be8c2..d43d372c2e 100644
--- a/pgxn/neon/walproposer_pg.c
+++ b/pgxn/neon/walproposer_pg.c
@@ -110,6 +110,9 @@ static void rm_safekeeper_event_set(Safekeeper *to_remove, bool is_sk);
 
 static void CheckGracefulShutdown(WalProposer *wp);
 
+// HADRON
+shardno_t get_num_shards(void);
+
 static void
 init_walprop_config(bool syncSafekeepers)
 {
@@ -646,18 +649,19 @@ walprop_pg_get_shmem_state(WalProposer *wp)
  * Record new ps_feedback in the array with shards and update min_feedback.
  */
 static PageserverFeedback
-record_pageserver_feedback(PageserverFeedback *ps_feedback)
+record_pageserver_feedback(PageserverFeedback *ps_feedback, shardno_t num_shards)
 {
 	PageserverFeedback min_feedback;
 
 	Assert(ps_feedback->present);
 	Assert(ps_feedback->shard_number < MAX_SHARDS);
+	Assert(ps_feedback->shard_number < num_shards);
 
 	SpinLockAcquire(&walprop_shared->mutex);
 
-	/* Update the number of shards */
-	if (ps_feedback->shard_number + 1 > walprop_shared->num_shards)
-		walprop_shared->num_shards = ps_feedback->shard_number + 1;
+	// Hadron: Update the num_shards from the source-of-truth (shard map) lazily when we receive 
+	// a new pageserver feedback.
+	walprop_shared->num_shards = Max(walprop_shared->num_shards, num_shards);
 
 	/* Update the feedback */
 	memcpy(&walprop_shared->shard_ps_feedback[ps_feedback->shard_number], ps_feedback, sizeof(PageserverFeedback));
@@ -2023,19 +2027,43 @@ walprop_pg_process_safekeeper_feedback(WalProposer *wp, Safekeeper *sk)
 	if (wp->config->syncSafekeepers)
 		return;
 
+
 	/* handle fresh ps_feedback */
 	if (sk->appendResponse.ps_feedback.present)
 	{
-		PageserverFeedback min_feedback = record_pageserver_feedback(&sk->appendResponse.ps_feedback);
+		shardno_t num_shards = get_num_shards();
 
-		/* Only one main shard sends non-zero currentClusterSize */
-		if (sk->appendResponse.ps_feedback.currentClusterSize > 0)
-			SetNeonCurrentClusterSize(sk->appendResponse.ps_feedback.currentClusterSize);
-
-		if (min_feedback.disk_consistent_lsn != standby_apply_lsn)
+		// During shard split, we receive ps_feedback from child shards before
+		// the split commits and our shard map GUC has been updated. We must
+		// filter out such feedback here because record_pageserver_feedback()
+		// doesn't do it.
+		//
+		// NB: what we would actually want to happen is that we only receive
+		// ps_feedback from the parent shards when the split is committed, then
+		// apply the split to our set of tracked feedback and from here on only
+		// receive ps_feedback from child shards. This filter condition doesn't
+		// do that: if we split from N parent to 2N child shards, the first N
+		// child shards' feedback messages will pass this condition, even before
+		// the split is committed. That's a bit sloppy, but OK for now.
+		if (sk->appendResponse.ps_feedback.shard_number < num_shards)
 		{
-			standby_apply_lsn = min_feedback.disk_consistent_lsn;
-			needToAdvanceSlot = true;
+			PageserverFeedback min_feedback = record_pageserver_feedback(&sk->appendResponse.ps_feedback, num_shards);
+
+			/* Only one main shard sends non-zero currentClusterSize */
+			if (sk->appendResponse.ps_feedback.currentClusterSize > 0)
+				SetNeonCurrentClusterSize(sk->appendResponse.ps_feedback.currentClusterSize);
+	
+			if (min_feedback.disk_consistent_lsn != standby_apply_lsn)
+			{
+				standby_apply_lsn = min_feedback.disk_consistent_lsn;
+				needToAdvanceSlot = true;
+			}
+		}
+		else
+		{
+			// HADRON
+			elog(DEBUG2, "Ignoring pageserver feedback for unknown shard %d (current shard number %d)",
+				sk->appendResponse.ps_feedback.shard_number, num_shards);
 		}
 	}