diff --git a/specs/phase0/beacon-chain.md b/specs/phase0/beacon-chain.md
index 4db18228c..15c8924a4 100644
--- a/specs/phase0/beacon-chain.md
+++ b/specs/phase0/beacon-chain.md
@@ -1718,10 +1718,10 @@ def process_attester_slashing(state: BeaconState, attester_slashing: AttesterSla
 ```python
 def process_attestation(state: BeaconState, attestation: Attestation) -> None:
     data = attestation.data
-    assert data.index < get_committee_count_per_slot(state, data.target.epoch)
     assert data.target.epoch in (get_previous_epoch(state), get_current_epoch(state))
     assert data.target.epoch == compute_epoch_at_slot(data.slot)
     assert data.slot + MIN_ATTESTATION_INCLUSION_DELAY <= state.slot <= data.slot + SLOTS_PER_EPOCH
+    assert data.index < get_committee_count_per_slot(state, data.target.epoch)
 
     committee = get_beacon_committee(state, data.slot, data.index)
     assert len(attestation.aggregation_bits) == len(committee)