diff --git a/src/ast/sls/sat_ddfw.cpp b/src/ast/sls/sat_ddfw.cpp
index 4d5c948d9..c5faa1c4e 100644
--- a/src/ast/sls/sat_ddfw.cpp
+++ b/src/ast/sls/sat_ddfw.cpp
@@ -270,6 +270,7 @@ namespace sat {
 
     void ddfw::flip(bool_var v) {
         ++m_flips;
+        m_vars[v].m_timestamp = m_flips;
         m_limit.inc();
         literal lit = literal(v, !value(v));
         literal nlit = ~lit;