diff --git a/src/ast/rewriter/seq_rewriter.cpp b/src/ast/rewriter/seq_rewriter.cpp
index e04df9791..a446b94bc 100644
--- a/src/ast/rewriter/seq_rewriter.cpp
+++ b/src/ast/rewriter/seq_rewriter.cpp
@@ -437,28 +437,26 @@ br_status seq_rewriter::mk_bool_app_helper(bool is_and, unsigned n, expr* const*
     
     for (unsigned i = 0; i < n; ++i) {
         expr* args_i = args[i];
-        expr* x = nullptr;
-        expr* y = nullptr;
-        expr* z = nullptr;
-        if (str().is_in_re(args_i, x, y)) {
+        expr* x = nullptr, *y = nullptr, *z = nullptr;
+        if (str().is_in_re(args_i, x, y) && !str().is_empty(x)) {
             if (in_re.find(x, z)) {				
                 in_re[x] = is_and ? re().mk_inter(z, y) : re().mk_union(z, y);
                 found_pair = true;
             }
             else {
                 in_re.insert(x, y);
+                found_pair |= not_in_re.contains(x);
             }
-            found_pair |= not_in_re.contains(x);
         }
-        else if (m().is_not(args_i, arg) && str().is_in_re(arg, x, y)) {
+        else if (m().is_not(args_i, arg) && str().is_in_re(arg, x, y) && !str().is_empty(x)) {
             if (not_in_re.find(x, z)) {
                 not_in_re[x] = is_and ? re().mk_union(z, y) : re().mk_inter(z, y);
                 found_pair = true;
             }
             else {
                 not_in_re.insert(x, y);
+                found_pair |= in_re.contains(x);
             }
-            found_pair |= in_re.contains(x);
         }
     }
     
diff --git a/src/math/lp/nla_core.cpp b/src/math/lp/nla_core.cpp
index 00db7bc42..24227da11 100644
--- a/src/math/lp/nla_core.cpp
+++ b/src/math/lp/nla_core.cpp
@@ -1497,7 +1497,7 @@ lbool core::check(vector<lemma>& l_vec) {
             m_tangents.tangent_lemma();
     }
 
-    if (l_vec.empty() && !done() && m_nla_settings.run_nra()) {
+    if (!done() && m_nla_settings.run_nra()) {
         ret = m_nra.check();
         m_stats.m_nra_calls ++;
     }
diff --git a/src/math/lp/nra_solver.cpp b/src/math/lp/nra_solver.cpp
index 9b96671d3..2ea7d5c10 100644
--- a/src/math/lp/nra_solver.cpp
+++ b/src/math/lp/nra_solver.cpp
@@ -73,6 +73,8 @@ struct solver::imp {
         }
         // TBD: add variable bounds?
 
+        m_nlsat->display(std::cout);
+
         lbool r = l_undef;
         try {
             r = m_nlsat->check();