diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c
index 9923994b50..5d8fd2fb72 100644
--- a/src/backend/access/heap/vacuumlazy.c
+++ b/src/backend/access/heap/vacuumlazy.c
@@ -1698,7 +1698,8 @@ retry:
 					}
 
 					/* Track newest xmin on page. */
-					if (TransactionIdFollows(xmin, prunestate->visibility_cutoff_xid))
+					if (TransactionIdFollows(xmin, prunestate->visibility_cutoff_xid) &&
+						TransactionIdIsNormal(xmin))
 						prunestate->visibility_cutoff_xid = xmin;
 				}
 				break;
@@ -1863,7 +1864,7 @@ retry:
 		 * because visibility_cutoff_xid will be logged by our caller in a
 		 * moment.
 		 */
-		Assert(cutoff == FrozenTransactionId ||
+		Assert(!TransactionIdIsValid(cutoff) ||
 			   cutoff == prunestate->visibility_cutoff_xid);
 	}
 #endif
@@ -3293,7 +3294,8 @@ heap_page_is_all_visible(LVRelState *vacrel, Buffer buf,
 					}
 
 					/* Track newest xmin on page. */
-					if (TransactionIdFollows(xmin, *visibility_cutoff_xid))
+					if (TransactionIdFollows(xmin, *visibility_cutoff_xid) &&
+						TransactionIdIsNormal(xmin))
 						*visibility_cutoff_xid = xmin;
 
 					/* Check whether this tuple is already frozen or not */
diff --git a/src/backend/storage/ipc/standby.c b/src/backend/storage/ipc/standby.c
index f43229dfda..ede00fee93 100644
--- a/src/backend/storage/ipc/standby.c
+++ b/src/backend/storage/ipc/standby.c
@@ -493,6 +493,7 @@ ResolveRecoveryConflictWithSnapshot(TransactionId snapshotConflictHorizon,
 	if (!TransactionIdIsValid(snapshotConflictHorizon))
 		return;
 
+	Assert(TransactionIdIsNormal(snapshotConflictHorizon));
 	backends = GetConflictingVirtualXIDs(snapshotConflictHorizon,
 										 locator.dbOid);
 	ResolveRecoveryConflictWithVirtualXIDs(backends,