diff --git a/src/app-layer.c b/src/app-layer.c
index 0be5acf611..a21ba3a80e 100644
--- a/src/app-layer.c
+++ b/src/app-layer.c
@@ -203,9 +203,11 @@ static void TCPProtoDetectCheckBailConditions(ThreadVars *tv,
         return;
     }
 
-    uint32_t size_ts = ssn->client.last_ack - ssn->client.isn - 1;
-    uint32_t size_tc = ssn->server.last_ack - ssn->server.isn - 1;
-    SCLogDebug("size_ts %u, size_tc %u", size_ts, size_tc);
+    const uint64_t size_ts = STREAM_HAS_SEEN_DATA(&ssn->client) ?
+        STREAM_RIGHT_EDGE(&ssn->client) : 0;
+    const uint64_t size_tc = STREAM_HAS_SEEN_DATA(&ssn->server) ?
+        STREAM_RIGHT_EDGE(&ssn->server) : 0;
+    SCLogDebug("size_ts %"PRIu64", size_tc %"PRIu64, size_ts, size_tc);
 
 #ifdef DEBUG_VALIDATION
     if (!(ssn->client.flags & STREAMTCP_STREAM_FLAG_GAP))