diff --git a/beacon_node/beacon_chain/src/beacon_chain.rs b/beacon_node/beacon_chain/src/beacon_chain.rs
index 614cc46d81..7c2336a28b 100644
--- a/beacon_node/beacon_chain/src/beacon_chain.rs
+++ b/beacon_node/beacon_chain/src/beacon_chain.rs
@@ -475,11 +475,7 @@ where
     /// Produce an `AttestationData` that is valid for the present `slot` and given `shard`.
     pub fn produce_attestation_data(&self, shard: u64) -> Result<AttestationData, Error> {
         trace!("BeaconChain::produce_attestation: shard: {}", shard);
-        let source_epoch = self.state.read().current_justified_epoch;
-        let source_root = *self.state.read().get_block_root(
-            source_epoch.start_slot(self.spec.slots_per_epoch),
-            &self.spec,
-        )?;
+        let state = self.state.read();
 
         let target_root = *self.state.read().get_block_root(
             self.state
@@ -500,8 +496,8 @@ where
                 epoch: self.state.read().slot.epoch(self.spec.slots_per_epoch),
                 crosslink_data_root: Hash256::zero(),
             },
-            source_epoch,
-            source_root,
+            source_epoch: state.current_justified_epoch,
+            source_root: state.current_justified_root,
         })
     }
 
@@ -696,7 +692,10 @@ where
             },
         };
 
-        trace!("BeaconChain::produce_block: updating state for new block.",);
+        debug!(
+            "Produced block with {} attestations, updating state.",
+            block.body.attestations.len()
+        );
 
         per_block_processing_without_verifying_block_signature(&mut state, &block, &self.spec)?;
 
diff --git a/eth2/types/src/attestation_duty.rs b/eth2/types/src/attestation_duty.rs
index 9612dd868c..299fdd44cf 100644
--- a/eth2/types/src/attestation_duty.rs
+++ b/eth2/types/src/attestation_duty.rs
@@ -6,5 +6,5 @@ pub struct AttestationDuty {
     pub slot: Slot,
     pub shard: Shard,
     pub committee_index: usize,
-    pub comittee_size: usize,
+    pub committee_len: usize,
 }
diff --git a/eth2/types/src/beacon_state/epoch_cache.rs b/eth2/types/src/beacon_state/epoch_cache.rs
index 32d9a643e9..62df902714 100644
--- a/eth2/types/src/beacon_state/epoch_cache.rs
+++ b/eth2/types/src/beacon_state/epoch_cache.rs
@@ -92,6 +92,7 @@ impl EpochCache {
                         slot,
                         shard,
                         committee_index: k,
+                        committee_len: crosslink_committee.committee.len(),
                     };
                     attestation_duties[*validator_index] = Some(attestation_duty)
                 }
diff --git a/eth2/utils/boolean-bitfield/src/lib.rs b/eth2/utils/boolean-bitfield/src/lib.rs
index cdd0bc3d77..d90b28dc5b 100644
--- a/eth2/utils/boolean-bitfield/src/lib.rs
+++ b/eth2/utils/boolean-bitfield/src/lib.rs
@@ -33,9 +33,11 @@ impl BooleanBitfield {
     }
 
     /// Create a new bitfield with the given length `initial_len` and all values set to `bit`.
-    pub fn from_elem(inital_len: usize, bit: bool) -> Self {
+    pub fn from_elem(initial_len: usize, bit: bool) -> Self {
+        // BitVec can panic if we don't set the len to be a multiple of 8.
+        let len = ((initial_len + 7) / 8) * 8;
         Self {
-            0: BitVec::from_elem(inital_len, bit),
+            0: BitVec::from_elem(len, bit),
         }
     }
 
diff --git a/validator_client/src/attester_service/mod.rs b/validator_client/src/attester_service/mod.rs
index 7178e28d73..20488b1c19 100644
--- a/validator_client/src/attester_service/mod.rs
+++ b/validator_client/src/attester_service/mod.rs
@@ -3,6 +3,7 @@ mod beacon_node_attestation;
 
 use std::sync::Arc;
 use types::{BeaconBlock, ChainSpec, Domain, Fork, Slot};
+use super::block_proposer::beacon_node_block::BeaconNodeError;
 
 #[derive(Debug, PartialEq)]
 pub enum Error {