diff --git a/openair2/LAYER2/NR_MAC_gNB/mac_rrc_dl_handler.c b/openair2/LAYER2/NR_MAC_gNB/mac_rrc_dl_handler.c
index 2435ed629a..426a72f391 100644
--- a/openair2/LAYER2/NR_MAC_gNB/mac_rrc_dl_handler.c
+++ b/openair2/LAYER2/NR_MAC_gNB/mac_rrc_dl_handler.c
@@ -743,7 +743,7 @@ void dl_rrc_message_transfer(const f1ap_dl_rrc_message_t *dl_rrc)
      * the new UE context (with new C-RNTI), but set up everything to reuse the
      * old config. */
     NR_UE_info_t *oldUE = find_nr_UE(&mac->UE_info, *dl_rrc->old_gNB_DU_ue_id);
-    DevAssert(oldUE);
+    AssertFatal(oldUE, "CU claims we should know UE %04x, but we don't\n", *dl_rrc->old_gNB_DU_ue_id);
     pthread_mutex_lock(&mac->sched_lock);
     /* 38.331 5.3.7.2 says that the UE releases the spCellConfig, so we drop it
      * from the current configuration. Also, expect the reconfiguration from