diff --git a/subsys/bluetooth/controller/ll_sw/ull_conn.c b/subsys/bluetooth/controller/ll_sw/ull_conn.c
index d904a566214..02b71d76402 100644
--- a/subsys/bluetooth/controller/ll_sw/ull_conn.c
+++ b/subsys/bluetooth/controller/ll_sw/ull_conn.c
@@ -2789,6 +2789,11 @@ static inline void event_phy_req_prep(struct ll_conn *conn)
 
 	case LLCP_PHY_STATE_UPD:
 	{
+		/* Defer if another procedure in progress */
+		if (conn->llcp_ack != conn->llcp_req) {
+			return;
+		}
+
 		/* Procedure complete */
 		conn->llcp_phy.ack = conn->llcp_phy.req;