diff --git a/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_ulsch.c b/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_ulsch.c
index e0ac0c7381..16a77cdfcf 100644
--- a/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_ulsch.c
+++ b/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_ulsch.c
@@ -1293,8 +1293,13 @@ bool nr_fr1_ulsch_preprocessor(module_id_t module_id, frame_t frame, sub_frame_t
   if (!is_xlsch_in_slot(nr_mac->ulsch_slot_bitmap[sched_slot / 64], sched_slot))
     return false;
 
-  bool is_mixed_slot = is_xlsch_in_slot(nr_mac->dlsch_slot_bitmap[sched_slot / 64], sched_slot) &&
-                        is_xlsch_in_slot(nr_mac->ulsch_slot_bitmap[sched_slot / 64], sched_slot);
+  bool is_mixed_slot = false;
+  const NR_TDD_UL_DL_Pattern_t *tdd =
+      scc->tdd_UL_DL_ConfigurationCommon ? &scc->tdd_UL_DL_ConfigurationCommon->pattern1 : NULL;
+
+  if (tdd)
+    is_mixed_slot = is_xlsch_in_slot(nr_mac->dlsch_slot_bitmap[sched_slot / 64], sched_slot) &&
+                    is_xlsch_in_slot(nr_mac->ulsch_slot_bitmap[sched_slot / 64], sched_slot);
 
   // FIXME: Avoid mixed slots for initialUplinkBWP
   if (sched_ctrl->active_ubwp==NULL && is_mixed_slot)