diff --git a/src/muz/spacer/spacer_context.cpp b/src/muz/spacer/spacer_context.cpp
index 9f73a9f9b..c15506eef 100644
--- a/src/muz/spacer/spacer_context.cpp
+++ b/src/muz/spacer/spacer_context.cpp
@@ -2594,6 +2594,7 @@ void context::init_global_smt_params() {
         p.set_bool("arith.eager_eq_axioms", false);
     }
     p.set_uint("random_seed", m_params.spacer_random_seed());
+    p.set_bool("clause_proof", false);
 
     p.set_bool("dump_benchmarks", m_params.spacer_dump_benchmarks());
     p.set_double("dump_threshold", m_params.spacer_dump_threshold());
diff --git a/src/smt/smt_model_finder.cpp b/src/smt/smt_model_finder.cpp
index 5e10aeb8a..f037a580d 100644
--- a/src/smt/smt_model_finder.cpp
+++ b/src/smt/smt_model_finder.cpp
@@ -2383,6 +2383,7 @@ namespace smt {
                 if (m.is_lambda_def(q)) return;
                 expr * e = q->get_expr();
                 reset_cache();
+                if (!m.inc()) return;
                 SASSERT(m_ttodo.empty());
                 SASSERT(m_ftodo.empty());
 
diff --git a/src/smt/theory_seq.cpp b/src/smt/theory_seq.cpp
index 21497fd6e..fa68fa53c 100644
--- a/src/smt/theory_seq.cpp
+++ b/src/smt/theory_seq.cpp
@@ -5883,13 +5883,12 @@ void theory_seq::push_lit_as_expr(literal l, expr_ref_vector& buf) {
 void theory_seq::add_axiom(literal l1, literal l2, literal l3, literal l4, literal l5) {
     context& ctx = get_context();
     literal_vector lits;
-    expr_ref_vector exprs(m);
     if (l1 == true_literal || l2 == true_literal || l3 == true_literal || l4 == true_literal || l5 == true_literal) return;
-    if (l1 != null_literal && l1 != false_literal) { ctx.mark_as_relevant(l1); lits.push_back(l1); push_lit_as_expr(l1, exprs); }
-    if (l2 != null_literal && l2 != false_literal) { ctx.mark_as_relevant(l2); lits.push_back(l2); push_lit_as_expr(l2, exprs); }
-    if (l3 != null_literal && l3 != false_literal) { ctx.mark_as_relevant(l3); lits.push_back(l3); push_lit_as_expr(l3, exprs); }
-    if (l4 != null_literal && l4 != false_literal) { ctx.mark_as_relevant(l4); lits.push_back(l4); push_lit_as_expr(l4, exprs); }
-    if (l5 != null_literal && l5 != false_literal) { ctx.mark_as_relevant(l5); lits.push_back(l5); push_lit_as_expr(l5, exprs); }
+    if (l1 != null_literal && l1 != false_literal) { ctx.mark_as_relevant(l1); lits.push_back(l1); }
+    if (l2 != null_literal && l2 != false_literal) { ctx.mark_as_relevant(l2); lits.push_back(l2); }
+    if (l3 != null_literal && l3 != false_literal) { ctx.mark_as_relevant(l3); lits.push_back(l3); }
+    if (l4 != null_literal && l4 != false_literal) { ctx.mark_as_relevant(l4); lits.push_back(l4); }
+    if (l5 != null_literal && l5 != false_literal) { ctx.mark_as_relevant(l5); lits.push_back(l5); }
     TRACE("seq", ctx.display_literals_verbose(tout << "assert:", lits) << "\n";);
     
     IF_VERBOSE(10, verbose_stream() << "ax ";
@@ -5898,7 +5897,7 @@ void theory_seq::add_axiom(literal l1, literal l2, literal l3, literal l4, liter
     m_new_propagation = true;
     ++m_stats.m_add_axiom;
     
-    std::function<expr*(void)> fn = [&]() { return m.mk_or(exprs.size(), exprs.c_ptr()); };
+    std::function<literal_vector(void)> fn = [&]() { return lits; };
     scoped_trace_stream _sts(*this, fn);
     validate_axiom(lits);
     ctx.mk_th_axiom(get_id(), lits.size(), lits.c_ptr());    
@@ -6469,7 +6468,6 @@ void theory_seq::propagate_not_prefix(expr* e) {
     add_axiom(lit, e1_gt_e2, ~mk_eq(c, d, false));
 }
 
-
 /*
   !suffix(e1,e2) => e1 != ""
   !suffix(e1,e2) => len(e1) > len(e2) or e1 = ycx & e2 = zdx & c != d