diff --git a/eth2/state_processing/src/per_block_processing/validate_attestation.rs b/eth2/state_processing/src/per_block_processing/validate_attestation.rs
index 9d1321407..68a51b2df 100644
--- a/eth2/state_processing/src/per_block_processing/validate_attestation.rs
+++ b/eth2/state_processing/src/per_block_processing/validate_attestation.rs
@@ -142,12 +142,10 @@ fn validate_attestation_signature_optional(
     );
 
     // Get the committee for the specific shard that this attestation is for.
+    let relative_epoch = RelativeEpoch::from_slot(state.slot, attestation.data.slot, spec)
+        .map_err(|_| BeaconStateError::EpochOutOfBounds)?; // Should not fail due to previous checks.
     let crosslink_committee = state
-        .get_crosslink_committees_at_slot(
-            attestation.data.slot,
-            RelativeEpoch::NextWithoutRegistryChange,
-            spec,
-        )?
+        .get_crosslink_committees_at_slot(attestation.data.slot, relative_epoch, spec)?
         .iter()
         .find(|c| c.shard == attestation.data.shard)
         .ok_or_else(|| {