diff --git a/hathor/manager.py b/hathor/manager.py
index 26b9a8c49..4ab9ec23e 100644
--- a/hathor/manager.py
+++ b/hathor/manager.py
@@ -732,6 +732,7 @@ def _make_block_template(self, parent_block: Block, parent_txs: 'ParentTxs', cur
         if __debug__ and len(parents) == 3:
             assert len(parents_any) == 0, 'Extra parents to choose from that cannot be chosen'
         score = parent_block_metadata.score + weight_to_work(weight)
+        self.rng.shuffle(parents_any)  # shuffle parents_any to get rid of biases if clients don't shuffle themselves
         return BlockTemplate(
             versions={TxVersion.REGULAR_BLOCK.value, TxVersion.MERGE_MINED_BLOCK.value},
             reward=self.daa.get_tokens_issued_per_block(height),