diff --git a/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_phytest.c b/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_phytest.c
index 16a975dc6e..6d6c6a2047 100644
--- a/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_phytest.c
+++ b/openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_phytest.c
@@ -60,6 +60,12 @@ void nr_preprocessor_phytest(module_id_t module_id,
   NR_UE_DL_BWP_t *dl_bwp = &UE->current_DL_BWP;
   const int CC_id = 0;
 
+  /* return if all DL HARQ processes wait for feedback */
+  if (sched_ctrl->retrans_dl_harq.head == -1 && sched_ctrl->available_dl_harq.head == -1) {
+    LOG_D(NR_MAC, "[UE %04x][%4d.%2d] UE has no free DL HARQ process, skipping\n", UE->rnti, frame, slot);
+    return;
+  }
+
   const int tda = get_dl_tda(RC.nrmac[module_id], scc, slot);
   NR_tda_info_t tda_info = get_dl_tda_info(dl_bwp,
                                            sched_ctrl->search_space->searchSpaceType->present,
@@ -216,6 +222,12 @@ bool nr_ul_preprocessor_phytest(module_id_t module_id, frame_t frame, sub_frame_
   NR_UE_UL_BWP_t *ul_bwp = &UE->current_UL_BWP;
   const int mu = ul_bwp->scs;
 
+  /* return if all UL HARQ processes wait for feedback */
+  if (sched_ctrl->retrans_ul_harq.head == -1 && sched_ctrl->available_ul_harq.head == -1) {
+    LOG_D(NR_MAC, "[UE %04x][%4d.%2d] UE has no free UL HARQ process, skipping\n", UE->rnti, frame, slot);
+    return false;
+  }
+
   NR_PUSCH_TimeDomainResourceAllocationList_t *tdaList = get_ul_tdalist(ul_bwp,
                                                                         sched_ctrl->coreset->controlResourceSetId,
                                                                         sched_ctrl->search_space->searchSpaceType->present,