Take ref to connected subchannel if subchannel starts in state READY.

src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc

@@ -312,11 +312,6 @@ static void pf_update_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
               exec_ctx, p->subchannel_list, "pf_update_includes_selected");
         }
         p->subchannel_list = subchannel_list;
-        if (p->selected->connected_subchannel != NULL) {
-          sd->connected_subchannel = GRPC_CONNECTED_SUBCHANNEL_REF(
-              grpc_subchannel_get_connected_subchannel(sd->subchannel),
-              "pf_update_includes_selected");
-        }
         p->selected = sd;
         destroy_unselected_subchannels_locked(exec_ctx, p);
         // If there was a previously pending update (which may or may

src/core/ext/filters/client_channel/lb_policy/subchannel_list.cc

@@ -179,6 +179,11 @@ grpc_lb_subchannel_list *grpc_lb_subchannel_list_create(
     sd->prev_connectivity_state = GRPC_CHANNEL_INIT;
     sd->curr_connectivity_state = subchannel_connectivity_state;
     sd->pending_connectivity_state_unsafe = subchannel_connectivity_state;
+    if (sd->curr_connectivity_state == GRPC_CHANNEL_READY) {
+      sd->connected_subchannel = GRPC_CONNECTED_SUBCHANNEL_REF(
+          grpc_subchannel_get_connected_subchannel(sd->subchannel),
+          "ready_at_sl_creation");
+    }
     sd->user_data_vtable = addresses->user_data_vtable;
     if (sd->user_data_vtable != NULL) {
       sd->user_data =