diff --git a/src/fri/recursive_verifier.rs b/src/fri/recursive_verifier.rs
index bfe0275f..acc4268e 100644
--- a/src/fri/recursive_verifier.rs
+++ b/src/fri/recursive_verifier.rs
@@ -145,12 +145,6 @@ impl<F: Extendable<D>, const D: usize> CircuitBuilder<F, D> {
             .enumerate()
         {
             self.set_context(&format!("Verify {}-th initial Merkle proof.", i));
-            if i == 0 {
-                self.add_marked(Arc::new(evals.clone()), "Evals");
-                self.add_marked(Arc::new(merkle_proof.siblings.clone()), "merkle proof");
-                self.add_marked(Arc::new(root.clone()), "root");
-                self.add_marked(Arc::new(x_index.clone()), "x_index");
-            }
             self.verify_merkle_proof(evals.clone(), x_index, root, merkle_proof);
         }
     }
diff --git a/src/hash.rs b/src/hash.rs
index 47d703cd..eb8e146b 100644
--- a/src/hash.rs
+++ b/src/hash.rs
@@ -1,5 +1,7 @@
 //! Concrete instantiation of a hash function.
 
+use std::sync::Arc;
+
 use crate::circuit_builder::CircuitBuilder;
 use crate::field::extension_field::Extendable;
 use crate::field::field::Field;
@@ -218,7 +220,7 @@ pub fn hash_n_to_m<F: Field>(mut inputs: Vec<F>, num_outputs: usize, pad: bool)
     // Absorb all input chunks.
     for input_chunk in inputs.chunks(SPONGE_RATE) {
         for i in 0..input_chunk.len() {
-            state[i] += input_chunk[i];
+            state[i] = input_chunk[i];
         }
         state = permute(state);
     }
diff --git a/src/merkle_proofs.rs b/src/merkle_proofs.rs
index 96d42a5f..9e355a0d 100644
--- a/src/merkle_proofs.rs
+++ b/src/merkle_proofs.rs
@@ -76,7 +76,6 @@ impl<F: Extendable<D>, const D: usize> CircuitBuilder<F, D> {
         let mut acc_leaf_index = zero;
 
         for (bit, &sibling) in purported_index_bits.into_iter().zip(&proof.siblings) {
-            self.add_marked(Arc::new(state), "current digest");
             let gate = self
                 .add_gate_no_constants(GMiMCGate::<F, D, GMIMC_ROUNDS>::with_automatic_constants());