diff --git a/qa/standalone/osd/pg-split-merge.sh b/qa/standalone/osd/pg-split-merge.sh
index 97583da048b..ad697a9fc3c 100755
--- a/qa/standalone/osd/pg-split-merge.sh
+++ b/qa/standalone/osd/pg-split-merge.sh
@@ -58,19 +58,30 @@ function TEST_a_merge_empty() {
 
     wait_for_clean || return 1
 
-    # now 1.0 is there but 1.1 is not
+    # osd.2: now 1.0 is there but 1.1 is not
+
+    # instantiate 1.1 on osd.2 with last_update=0'0 ('empty'), which is
+    # the problematic state... then let it merge with 1.0
     ceph tell osd.2 config set osd_debug_no_acting_change true
     ceph osd out 0 1
     ceph osd pool set foo pg_num 1
     sleep 5
     ceph tell osd.2 config set osd_debug_no_acting_change false
+
+    # go back to osd.1 being primary, and 3x so the osd.2 copy doesn't get
+    # removed
     ceph osd in 0 1
     ceph osd pool set foo size 3
 
     wait_for_clean || return 1
+
+    # scrub to ensure the osd.3 copy of 1.0 was incomplete (vs missing
+    # half of its objects).
     ceph pg scrub 1.0
-    sleep 5
-    ceph -s | grep inconsistent || return 1
+    sleep 10
+    ceph log last debug
+    ceph pg ls
+    ceph pg ls | grep ' active.clean ' || return 1
 }
 
 function TEST_import_after_merge_and_gap() {
diff --git a/src/osd/PG.cc b/src/osd/PG.cc
index 0fce841bafd..f68c4ba8ce0 100644
--- a/src/osd/PG.cc
+++ b/src/osd/PG.cc
@@ -2718,6 +2718,18 @@ void PG::merge_from(map<spg_t,PGRef>& sources, RecoveryCtx *rctx,
     dout(10) << __func__ << " target incomplete" << dendl;
     incomplete = true;
   }
+  if (info.pgid.pgid != last_pg_merge_meta.source_pgid.get_parent()) {
+    dout(10) << __func__ << " target doesn't match expected parent "
+	     << last_pg_merge_meta.source_pgid.get_parent()
+	     << " of source_pgid " << last_pg_merge_meta.source_pgid
+	     << dendl;
+    incomplete = true;
+  }
+  if (info.last_update != last_pg_merge_meta.target_version) {
+    dout(10) << __func__ << " target version doesn't match expected "
+	     << last_pg_merge_meta.target_version << dendl;
+    incomplete = true;
+  }
 
   PGLogEntryHandler handler{this, rctx->transaction};
   pg_log.roll_forward(&handler);
@@ -2741,6 +2753,17 @@ void PG::merge_from(map<spg_t,PGRef>& sources, RecoveryCtx *rctx,
 	       << dendl;
       incomplete = true;
     }
+    if (source->info.pgid.pgid != last_pg_merge_meta.source_pgid) {
+      dout(10) << __func__ << " source " << source->info.pgid.pgid
+	       << " doesn't match expected source pgid "
+	       << last_pg_merge_meta.source_pgid << dendl;
+      incomplete = true;
+    }
+    if (source->info.last_update != last_pg_merge_meta.source_version) {
+      dout(10) << __func__ << " source version doesn't match expected "
+	       << last_pg_merge_meta.target_version << dendl;
+      incomplete = true;
+    }
 
     // prepare log
     PGLogEntryHandler handler{source.get(), rctx->transaction};