diff --git a/src/math/lp/nra_solver.cpp b/src/math/lp/nra_solver.cpp
index f5cc61ba9e..8fb383d475 100644
--- a/src/math/lp/nra_solver.cpp
+++ b/src/math/lp/nra_solver.cpp
@@ -240,16 +240,26 @@ struct solver::imp {
             lra.init_model();
             for (lp::constraint_index ci : lra.constraints().indices())
                 if (!check_constraint(ci)) {
-                    IF_VERBOSE(0, verbose_stream() << "constraint " << ci << " violated\n";
-                               lra.constraints().display(verbose_stream()));
-                    UNREACHABLE();
+                    // nlsat only solves over the cone-of-influence (COI) subset
+                    // of constraints, so constraints outside the COI may be
+                    // legitimately violated by the nlsat model. Only a violation
+                    // of a COI constraint indicates a genuine nlsat bug; a
+                    // non-COI violation is benign, so fall back to l_undef
+                    // quietly without emitting diagnostics.
+                    if (m_coi.constraints().contains(ci)) {
+                        IF_VERBOSE(0, verbose_stream() << "constraint " << ci << " violated\n";
+                                   lra.constraints().display(verbose_stream()));
+                        UNREACHABLE();
+                    }
                     return l_undef;
                 }
             for (auto const &m : m_nla_core.emons()) {
                 if (!check_monic(m)) {
-                    IF_VERBOSE(0, verbose_stream() << "monic " << m << " violated\n";
-                               lra.constraints().display(verbose_stream()));
-                    UNREACHABLE();
+                    if (m_coi.mons().contains(m.var())) {
+                        IF_VERBOSE(0, verbose_stream() << "monic " << m << " violated\n";
+                                   lra.constraints().display(verbose_stream()));
+                        UNREACHABLE();
+                    }
                     return l_undef;
                 }
             }