diff --git a/src/cmd_context/context_params.cpp b/src/cmd_context/context_params.cpp
index dc3880674..c0ab1e3e2 100644
--- a/src/cmd_context/context_params.cpp
+++ b/src/cmd_context/context_params.cpp
@@ -37,6 +37,7 @@ context_params::context_params() {
     m_model_compress = true;
     m_timeout = UINT_MAX;
     m_rlimit  = 0;
+    m_statistics = false;
     updt_params();
 }
 
@@ -109,6 +110,9 @@ void context_params::set(char const * param, char const * value) {
     else if (p == "dump_models") {
         set_bool(m_dump_models, param, value);
     }
+    else if (p == "stats") {
+        set_bool(m_statistics, param, value);
+    }
     else if (p == "trace") {
         set_bool(m_trace, param, value);
     }
@@ -158,6 +162,7 @@ void context_params::updt_params(params_ref const & p) {
     m_unsat_core        = p.get_bool("unsat_core", m_unsat_core);
     m_debug_ref_count   = p.get_bool("debug_ref_count", m_debug_ref_count);
     m_smtlib2_compliant = p.get_bool("smtlib2_compliant", m_smtlib2_compliant);
+    m_statistics        = p.get_bool("stats", m_statistics);
 }
 
 void context_params::collect_param_descrs(param_descrs & d) {
@@ -174,6 +179,8 @@ void context_params::collect_param_descrs(param_descrs & d) {
     d.insert("dot_proof_file", CPK_STRING, "file in which to output graphical proofs", "proof.dot");
     d.insert("debug_ref_count", CPK_BOOL, "debug support for AST reference counting", "false");
     d.insert("smtlib2_compliant", CPK_BOOL, "enable/disable SMT-LIB 2.0 compliance", "false");
+    d.insert("stats", CPK_BOOL, "enable/disable statistics", "false");
+    // statistics are hidden as they are controlled by the /st option.
     collect_solver_param_descrs(d);
 }
 
diff --git a/src/cmd_context/context_params.h b/src/cmd_context/context_params.h
index 8ca36dfc9..f00d39641 100644
--- a/src/cmd_context/context_params.h
+++ b/src/cmd_context/context_params.h
@@ -45,6 +45,7 @@ public:
     bool        m_unsat_core;
     bool        m_smtlib2_compliant; // it must be here because it enable/disable the use of coercions in the ast_manager.
     unsigned    m_timeout;
+    bool        m_statistics;
 
     unsigned rlimit() const { return m_rlimit; }
     context_params();
diff --git a/src/muz/base/bind_variables.cpp b/src/muz/base/bind_variables.cpp
index cbafc57b0..1e918b172 100644
--- a/src/muz/base/bind_variables.cpp
+++ b/src/muz/base/bind_variables.cpp
@@ -64,7 +64,7 @@ expr_ref bind_variables::abstract(expr* term, cache_t& cache, unsigned scope) {
         }
         switch(e->get_kind()) {
         case AST_VAR: {
-            SASSERT(to_var(e)->get_idx() < scope); 
+            // SASSERT(to_var(e)->get_idx() >= scope); 
             // mixing bound variables and free is possible for the caller, 
             // but not proper use.
             // So we assert here even though we don't check for it.
diff --git a/src/muz/base/fp_params.pyg b/src/muz/base/fp_params.pyg
index dea7ad328..8cee99540 100644
--- a/src/muz/base/fp_params.pyg
+++ b/src/muz/base/fp_params.pyg
@@ -83,9 +83,9 @@ def_module_params('fp',
                           ('print_boogie_certificate', BOOL, False,
                            'print certificate for reachability or non-reachability using a ' +
                            'format understood by Boogie'),
-                          ('print_statistics',  BOOL, False, 'print statistics'),
                           ('print_aig', SYMBOL, '',
                            'Dump clauses in AIG text format (AAG) to the given file name'),
+                          ('print_statistics',  BOOL, False, 'print statistics'),
 	                  ('tab.selection', SYMBOL, 'weight',
                            'selection method for tabular strategy: weight (default), first, var-use'),
                           ('xform.bit_blast', BOOL, False,
diff --git a/src/muz/fp/dl_cmds.cpp b/src/muz/fp/dl_cmds.cpp
index 6fa4b39c4..231dca0d3 100644
--- a/src/muz/fp/dl_cmds.cpp
+++ b/src/muz/fp/dl_cmds.cpp
@@ -355,7 +355,7 @@ private:
     }
 
     void print_statistics(cmd_context& ctx) {
-        if (m_dl_ctx->get_params().print_statistics()) {
+        if (ctx.params().m_statistics) {
             statistics st;
             datalog::context& dlctx = m_dl_ctx->dlctx();
             dlctx.collect_statistics(st);
diff --git a/src/muz/spacer/spacer_context.cpp b/src/muz/spacer/spacer_context.cpp
index 693812a31..f0e86f1a5 100644
--- a/src/muz/spacer/spacer_context.cpp
+++ b/src/muz/spacer/spacer_context.cpp
@@ -2683,7 +2683,7 @@ lbool context::solve(unsigned from_lvl)
     if (m_last_result == l_true) {
         m_stats.m_cex_depth = get_cex_depth ();
     }
-
+ 
     if (m_params.print_statistics ()) {
         statistics st;
         collect_statistics (st);
@@ -3063,13 +3063,13 @@ lbool context::solve_core (unsigned from_lvl)
         IF_VERBOSE(1,verbose_stream() << "Entering level "<< lvl << "\n";);
 
         STRACE("spacer_progress", tout << "\n* LEVEL " << lvl << "\n";);
-
         IF_VERBOSE(1,
                    if (m_params.print_statistics ()) {
                        statistics st;
                        collect_statistics (st);
                    };
             );
+
     }
     // communicate failure to datalog::context
     if (m_context) { m_context->set_status(datalog::BOUNDED); }
diff --git a/src/sat/sat_solver/inc_sat_solver.cpp b/src/sat/sat_solver/inc_sat_solver.cpp
index 8b7e2e63c..ff55598c2 100644
--- a/src/sat/sat_solver/inc_sat_solver.cpp
+++ b/src/sat/sat_solver/inc_sat_solver.cpp
@@ -483,6 +483,7 @@ public:
         s2g(m_solver, m_map, m_params, g, m_sat_mc);
         m_internalized_fmls.reset();
         g.get_formulas(m_internalized_fmls);
+        TRACE("sat", m_solver.display(tout); tout << m_internalized_fmls << "\n";);
         m_internalized_converted = true;
     }
 
@@ -529,7 +530,7 @@ private:
             throw default_exception("generation of proof objects is not supported in this mode");
         }
         SASSERT(!g->proofs_enabled());
-        TRACE("sat", g->display(tout););
+        TRACE("sat", m_solver.display(tout); g->display(tout););
         try {
             (*m_preprocess)(g, m_subgoals);
         }
@@ -712,23 +713,35 @@ private:
         m_asms.reset();
         unsigned j = 0;
         sat::literal lit;
+        sat::literal_set seen;
         for (unsigned i = 0; i < sz; ++i) {
             if (dep2asm.find(asms[i], lit)) {
                 SASSERT(lit.var() <= m_solver.num_vars());
-                m_asms.push_back(lit);
-                if (i != j && !m_weights.empty()) {
-                    m_weights[j] = m_weights[i];
+                if (!seen.contains(lit)) {
+                    m_asms.push_back(lit);
+                    seen.insert(lit);
+                    if (i != j && !m_weights.empty()) {
+                        m_weights[j] = m_weights[i];
+                    }
+                    ++j;
                 }
-                ++j;
             }
         }
         for (unsigned i = 0; i < get_num_assumptions(); ++i) {
             if (dep2asm.find(get_assumption(i), lit)) {
                 SASSERT(lit.var() <= m_solver.num_vars());
-                m_asms.push_back(lit);
+                if (!seen.contains(lit)) {
+                    m_asms.push_back(lit);
+                    seen.insert(lit);
+                }
             }
         }
-
+        CTRACE("sat", dep2asm.size() != m_asms.size(), 
+               tout << dep2asm.size() << " vs " << m_asms.size() << "\n";
+               tout << m_asms << "\n";
+               for (auto const& kv : dep2asm) {
+                   tout << mk_pp(kv.m_key, m) << " " << kv.m_value << "\n";
+               });
         SASSERT(dep2asm.size() == m_asms.size());
     }
 
@@ -751,6 +764,7 @@ private:
                   tout << mk_pp(kv.m_key, m) << " |-> " << mk_pp(kv.m_value, m) << "\n";
               }
               tout << "core: "; for (auto c : core) tout << c << " ";  tout << "\n";
+              m_solver.display(tout);
               );
 
         m_core.reset();
diff --git a/src/sat/tactic/goal2sat.cpp b/src/sat/tactic/goal2sat.cpp
index 029ddf924..7faa89370 100644
--- a/src/sat/tactic/goal2sat.cpp
+++ b/src/sat/tactic/goal2sat.cpp
@@ -1167,7 +1167,7 @@ struct sat2goal::imp {
     }
 
     void operator()(sat::solver & s, atom2bool_var const & map, goal & r, ref<mc> & mc) {
-        if (s.inconsistent()) {
+        if (s.at_base_lvl() && s.inconsistent()) {
             r.assert_expr(m.mk_false());
             return;
         }
diff --git a/src/shell/main.cpp b/src/shell/main.cpp
index f6c809bb2..bb1c19b47 100644
--- a/src/shell/main.cpp
+++ b/src/shell/main.cpp
@@ -199,6 +199,7 @@ void parse_cmd_line_args(int argc, char ** argv) {
             }
             else if (strcmp(opt_name, "st") == 0) {
                 g_display_statistics = true; 
+                gparams::set("stats", "true");
             }
             else if (strcmp(opt_name, "ist") == 0) {
                 g_display_istatistics = true;