diff --git a/src/muz/spacer/spacer_context.cpp b/src/muz/spacer/spacer_context.cpp
index 38b1c7149..0ef8c7992 100644
--- a/src/muz/spacer/spacer_context.cpp
+++ b/src/muz/spacer/spacer_context.cpp
@@ -3488,7 +3488,7 @@ lbool context::handle_unknown(pob &n, const datalog::rule *r, model &model) {
     }
     // model \models reach_fact && Tr && pob
     if (model.is_true(n.pt().get_transition(*r)) && model.is_true(n.post()) &&
-        n.pt().mk_mdl_rf_consistent(r, model)) {
+        r->get_uninterpreted_tail_size() == 0 && n.pt().mk_mdl_rf_consistent(r, model)) {
         return l_true;
     }
     return l_undef;