diff --git a/include/mmx/Harvester.h b/include/mmx/Harvester.h
index 21384bba1..2f8b95c31 100644
--- a/include/mmx/Harvester.h
+++ b/include/mmx/Harvester.h
@@ -67,6 +67,7 @@ class Harvester : public HarvesterBase {
 						const uint32_t score, const int64_t time_begin_ms) const;
 
 private:
+	bool is_ready = false;
 	hash_t harvester_id;
 	uint64_t total_bytes = 0;
 	uint64_t total_bytes_effective = 0;
diff --git a/src/Farmer.cpp b/src/Farmer.cpp
index dcebffbfe..9dec723e5 100644
--- a/src/Farmer.cpp
+++ b/src/Farmer.cpp
@@ -78,14 +78,16 @@ uint64_t Farmer::get_partial_diff(const addr_t& plot_nft) const
 			return stats.partial_diff;
 		}
 	}
-	return 1;
+	return 0;
 }
 
 std::map<addr_t, uint64_t> Farmer::get_partial_diffs(const std::vector<addr_t>& plot_nfts) const
 {
 	std::map<addr_t, uint64_t> out;
 	for(const auto& addr : plot_nfts) {
-		out[addr] = get_partial_diff(addr);
+		if(auto diff = get_partial_diff(addr)) {
+			out[addr] = diff;
+		}
 	}
 	return out;
 }
diff --git a/src/Harvester.cpp b/src/Harvester.cpp
index b9c79a474..7662ddb70 100644
--- a/src/Harvester.cpp
+++ b/src/Harvester.cpp
@@ -130,7 +130,7 @@ void Harvester::check_queue()
 
 void Harvester::handle(std::shared_ptr<const Challenge> value)
 {
-	if(value->max_delay < 2) {
+	if(!is_ready || value->max_delay < 2) {
 		return;
 	}
 	if(!already_checked.insert(value->challenge).second) {
@@ -643,8 +643,8 @@ void Harvester::reload()
 		}
 	}
 	for(const auto& entry : plot_map) {
-		if(auto contract = entry.second->get_contract()) {
-			plot_contract_set[*contract]++;
+		if(const auto& addr = entry.second->get_contract()) {
+			plot_contract_set[*addr]++;
 		}
 	}
 
@@ -653,8 +653,14 @@ void Harvester::reload()
 
 	// check challenges again for new plots
 	if(plots.size()) {
+		is_ready = false;
 		already_checked.clear();
 	}
+	if(!is_ready) {
+		set_timeout_millis(3000, [this]() {
+			is_ready = true;
+		});
+	}
 	log(INFO) << "[" << my_name << "] Loaded " << plot_map.size() << " plots, "
 			<< total_bytes / pow(1000, 4) << " TB, " << total_bytes_effective / pow(1000, 4) << " TBe, "
 			<< virtual_map.size() << " virtual plots, " << total_balance / pow(10, params->decimals) << " MMX total, took "
@@ -742,6 +748,7 @@ void Harvester::update_nfts()
 				}
 				if(--(*job) == 0) {
 					update();
+					set_timeout_millis(2000, std::bind(&Harvester::update, this));
 				}
 			},
 			[this, address](const std::exception& ex) {