diff --git a/src/math/polysat/conflict.cpp b/src/math/polysat/conflict.cpp
index 71122353f..410ff5f5a 100644
--- a/src/math/polysat/conflict.cpp
+++ b/src/math/polysat/conflict.cpp
@@ -211,8 +211,8 @@ namespace polysat {
     bool conflict::is_valid() const {
         SASSERT(!empty());
         // If m_dep is set, the corresponding constraint was asserted at m_level and is not valid earlier.
-        if (!m_dep.is_null())
-            return m_level <= s.m_level;
+        if (!m_dep.is_null() && m_level >= s.m_level)
+            return false;
         // All conflict constraints must be bool-assigned.
         for (unsigned lit_idx : m_literals)
             if (!s.m_bvars.is_assigned(sat::to_literal(lit_idx)))
@@ -636,8 +636,8 @@ namespace polysat {
                 if (s.m_bvars.is_assumption(lit)) {
                     // only assumptions have external dependencies
                     dependency const d = s.m_bvars.dep(lit);
-                    if (!d.is_null())
-                        deps.insert(d.val());
+                    if (!d.is_null()) 
+                        deps.insert(d.val());                    
                 }
                 else if (s.m_bvars.is_bool_propagation(lit)) {
                     IF_VERBOSE(11, verbose_stream() << "    reason " << *s.m_bvars.reason(lit) << "\n";);
diff --git a/src/math/polysat/solver.cpp b/src/math/polysat/solver.cpp
index dd60b11f5..70495437a 100644
--- a/src/math/polysat/solver.cpp
+++ b/src/math/polysat/solver.cpp
@@ -95,10 +95,33 @@ namespace polysat {
     }
 
     lbool solver::unit_propagate() {
+#if 1
         return l_undef;
-        // disabled to allow debugging unsoundness for watched literals
+#elif 1
+
+        unsigned level = m_level;
+        SASSERT(!m_is_solving);
+        backjump(base_level());
+        if (!is_conflict())
+            propagate();
+        VERIFY(level == m_level);
+        if (is_conflict()) {
+            ++m_stats.m_num_conflicts;
+            return l_false;
+        }
+        
+        return l_undef;
+#else
         flet<uint64_t> _max_d(m_config.m_max_conflicts, m_stats.m_num_conflicts + 2);
-        return check_sat();
+        unsigned level = m_level;
+        lbool r = check_sat();
+        if (r != l_false) {
+            backjump(level);
+            m_conflict.reset();
+        }
+        SASSERT(level == m_level);
+        return r;
+#endif
     }
 
     dd::pdd_manager& solver::sz2pdd(unsigned sz) const {
diff --git a/src/sat/smt/bv_polysat.cpp b/src/sat/smt/bv_polysat.cpp
index bda4362af..50161f046 100644
--- a/src/sat/smt/bv_polysat.cpp
+++ b/src/sat/smt/bv_polysat.cpp
@@ -220,7 +220,7 @@ namespace bv {
         force_push();
         pdd p = var2pdd(v1);
         pdd q = var2pdd(v2);
-        auto sc = m_polysat.eq(p, q);
+        auto sc = m_polysat.eq(p, q);        
         m_var_eqs.setx(m_var_eqs_head, std::make_pair(v1, v2), std::make_pair(v1, v2));
         ctx.push(value_trail<unsigned>(m_var_eqs_head));        
         m_polysat.assign_eh(sc, polysat::dependency(2 * m_var_eqs_head)); 
@@ -266,11 +266,13 @@ namespace bv {
         sat::literal_vector core;
         euf::enode_pair_vector eqs;
         m_polysat.unsat_core(deps);
-        for (auto n : deps) {
+        for (auto n : deps) {            
             if (0 != (n.val() & 1))
                 core.push_back(sat::to_literal(n.val() / 2));
-            else {
+            else {                
                 auto [v1, v2] = m_var_eqs[n.val() / 2];
+                VERIFY(var2enode(v1)->get_root() == var2enode(v2)->get_root());
+                VERIFY(n.val() <= 2 * m_var_eqs_head);
                 eqs.push_back(euf::enode_pair(var2enode(v1), var2enode(v2)));
             }
         }