diff --git a/core/lib/circuit/src/witness/utils.rs b/core/lib/circuit/src/witness/utils.rs
index cfd04f718b..b2f4348d54 100644
--- a/core/lib/circuit/src/witness/utils.rs
+++ b/core/lib/circuit/src/witness/utils.rs
@@ -788,5 +788,14 @@ pub fn build_block_witness<'a>(
         block.new_root_hash
     );
     witness_accum.calculate_pubdata_commitment();
+
+    let mut block_commitment = block.block_commitment.as_bytes().to_vec();
+    block_commitment[0] = block_commitment[0] & (0xffu8 >> 3);
+    let block_commitment = fr_from_bytes(block_commitment);
+    assert_eq!(
+        witness_accum.pubdata_commitment.unwrap(),
+        block_commitment,
+        "witness accumulator and server different commitment"
+    );
     Ok(witness_accum)
 }