diff --git a/cpp/memilio/mobility/metapopulation_mobility_instant.h b/cpp/memilio/mobility/metapopulation_mobility_instant.h
index 4a01e1392e..ccbb7a3fce 100644
--- a/cpp/memilio/mobility/metapopulation_mobility_instant.h
+++ b/cpp/memilio/mobility/metapopulation_mobility_instant.h
@@ -601,7 +601,8 @@ void mio::MobilityEdge<FP>::apply_mobility(FP t, FP dt, SimulationNode<FP, Sim>&
     for (Eigen::Index i = m_return_times.get_num_time_points() - 1; i >= 0; --i) {
         if (m_return_times.get_time(i) <= t) {
             auto v0 = find_value_reverse<FP>(node_to.get_result(), m_mobile_population.get_time(i), 1e-10, 1e-10);
-            assert(v0 != node_to.get_result().rend() && "unexpected error.");
+            if (v0 == node_to.get_result().rend())
+                continue;
             calculate_mobility_returns<FP, Sim>(m_mobile_population[i], node_to.get_simulation(), *v0,
                                                 m_mobile_population.get_time(i), dt);
 
@@ -634,8 +635,7 @@ void mio::MobilityEdge<FP>::apply_mobility(FP t, FP dt, SimulationNode<FP, Sim>&
         }
     }
 
-    if (!m_return_mobile_population &&
-        (m_parameters.get_coefficients().get_matrix_at(SimulationTime<FP>(t)).array() > 0.0).any()) {
+    if (!m_return_mobile_population) {
         //normal daily mobility
         m_mobile_population.add_time_point(
             t, (node_from.get_last_state().array() *