only do the watermark initialization for producers on this node

plugins/producer_plugin/producer_plugin.cpp

@@ -474,6 +474,7 @@ block_production_condition::block_production_condition_enum producer_plugin_impl
       flat_set<account_name> new_producers;
       new_producers.reserve(new_bs->active_schedule.producers.size());
       for( const auto& p: new_bs->active_schedule.producers) {
+         if (_producers.count(p.producer_name) > 0)
             new_producers.insert(p.producer_name);
       }