diff --git a/src/clientiface.cpp b/src/clientiface.cpp
index 8a1a62694..a3a17d435 100644
--- a/src/clientiface.cpp
+++ b/src/clientiface.cpp
@@ -370,17 +370,21 @@ queue_full_break:
 
 void RemoteClient::GotBlock(v3s16 p)
 {
-	if(m_blocks_sending.find(p) != m_blocks_sending.end())
-		m_blocks_sending.erase(p);
-	else
-	{
-		m_excess_gotblocks++;
+	if (m_blocks_modified.find(p) == m_blocks_modified.end()) {
+		if (m_blocks_sending.find(p) != m_blocks_sending.end())
+			m_blocks_sending.erase(p);
+		else
+			m_excess_gotblocks++;
+
+		m_blocks_sent.insert(p);
 	}
-	m_blocks_sent.insert(p);
 }
 
 void RemoteClient::SentBlock(v3s16 p)
 {
+	if (m_blocks_modified.find(p) != m_blocks_modified.end())
+		m_blocks_modified.erase(p);
+
 	if(m_blocks_sending.find(p) == m_blocks_sending.end())
 		m_blocks_sending[p] = 0.0;
 	else
@@ -397,6 +401,7 @@ void RemoteClient::SetBlockNotSent(v3s16 p)
 		m_blocks_sending.erase(p);
 	if(m_blocks_sent.find(p) != m_blocks_sent.end())
 		m_blocks_sent.erase(p);
+	m_blocks_modified.insert(p);
 }
 
 void RemoteClient::SetBlocksNotSent(std::map<v3s16, MapBlock*> &blocks)
@@ -409,6 +414,7 @@ void RemoteClient::SetBlocksNotSent(std::map<v3s16, MapBlock*> &blocks)
 			i != blocks.end(); ++i)
 	{
 		v3s16 p = i->first;
+		m_blocks_modified.insert(p);
 
 		if(m_blocks_sending.find(p) != m_blocks_sending.end())
 			m_blocks_sending.erase(p);
diff --git a/src/clientiface.h b/src/clientiface.h
index d7622cad3..c09942909 100644
--- a/src/clientiface.h
+++ b/src/clientiface.h
@@ -394,6 +394,16 @@ private:
 	*/
 	std::map<v3s16, float> m_blocks_sending;
 
+	/*
+		Blocks that have been modified since last sending them.
+		These blocks will not be marked as sent, even if the
+		client reports it has received them to account for blocks
+		that are being modified while on the line.
+
+		List of block positions.
+	*/
+	std::set<v3s16> m_blocks_modified;
+
 	/*
 		Count of excess GotBlocks().
 		There is an excess amount because the client sometimes