diff --git a/tests/linearizability/watch.go b/tests/linearizability/watch.go
index 6d63020f6..0b00bc5ef 100644
--- a/tests/linearizability/watch.go
+++ b/tests/linearizability/watch.go
@@ -83,9 +83,10 @@ func validateWatchResponses(t *testing.T, responses [][]watchResponse, expectPro
 
 func validateMemberWatchResponses(t *testing.T, responses []watchResponse, expectProgressNotify bool) {
 	var (
-		gotProgressNotify          = false
-		lastEventModRevision int64 = 1 // The event.Kv.ModRevision in the latest event.
-		lastHeadRevision     int64 = 1 // The resp.Header.Revision in last watch response.
+		gotProgressNotify                = false
+		lastEventModRevision       int64 = 1 // The event.Kv.ModRevision in the latest event.
+		lastHeadRevision           int64 = 1 // The resp.Header.Revision in last watch response.
+		lastProgressNotifyRevision int64 = 0 // The resp.Header.Revision in the last progress notify watch response.
 	)
 	for _, resp := range responses {
 		if resp.Header.Revision < lastHeadRevision {
@@ -104,6 +105,9 @@ func validateMemberWatchResponses(t *testing.T, responses []watchResponse, expec
 		}
 
 		for _, event := range resp.Events {
+			if event.Kv.ModRevision <= lastProgressNotifyRevision {
+				t.Errorf("BROKE: etcd will not send progress notification to a watcher until it has synced all events. So a watcher will never receive an event with a lower `ModRevision` than the last progressNotification's revision, eventRevision: %d, progressNotifyRevision: %d", event.Kv.ModRevision, lastProgressNotifyRevision)
+			}
 			if event.Kv.ModRevision != lastEventModRevision && event.Kv.ModRevision != lastEventModRevision+1 {
 				t.Errorf("Event mod revision should stay the same or increment by one, last: %d, current: %d", lastEventModRevision, event.Kv.ModRevision)
 			}
@@ -115,6 +119,9 @@ func validateMemberWatchResponses(t *testing.T, responses []watchResponse, expec
 				lastEventModRevision, resp.Header.Revision)
 		}
 
+		if resp.IsProgressNotify() {
+			lastProgressNotifyRevision = resp.Header.Revision
+		}
 		lastHeadRevision = resp.Header.Revision
 	}
 	if gotProgressNotify != expectProgressNotify {