Merge branch 'master' into Fix-4858

ethcore/src/engines/authority_round/mod.rs

@@ -521,7 +521,9 @@ impl Engine for AuthorityRound {
 		let parent_hash = block.fields().header.parent_hash().clone();
 		::engines::common::push_last_hash(block, last_hashes.clone(), self, &parent_hash)?;
 
-		if !epoch_begin { return Ok(()) }
+		// with immediate transitions, we don't use the epoch mechanism anyway.
+		// the genesis is always considered an epoch, but we ignore it intentionally.
+		if self.immediate_transitions || !epoch_begin { return Ok(()) }
 
 		// genesis is never a new block, but might as well check.
 		let header = block.fields().header.clone();