diff --git a/source/MAC/IEEE802_15_4/mac_mcps_sap.c b/source/MAC/IEEE802_15_4/mac_mcps_sap.c
index 862d70fe6fa..608dcd0e89f 100644
--- a/source/MAC/IEEE802_15_4/mac_mcps_sap.c
+++ b/source/MAC/IEEE802_15_4/mac_mcps_sap.c
@@ -1752,6 +1752,7 @@ int8_t mcps_generic_ack_build(protocol_interface_rf_mac_setup_s *rf_ptr, const m
     csma_params.cca_enabled = false;
     rf_ptr->dev_driver->phy_driver->extension(PHY_EXTENSION_SET_CSMA_PARAMETERS, (uint8_t*) &csma_params);
     if (rf_ptr->active_pd_data_request) {
+        timer_mac_stop(rf_ptr);
         mac_pd_sap_set_phy_tx_time(rf_ptr, 0, false);
     }
     return mcps_pd_data_cca_trig(rf_ptr, buffer);