diff --git a/specs/core/0_fork-choice.md b/specs/core/0_fork-choice.md
index 099843067..1793b51ff 100644
--- a/specs/core/0_fork-choice.md
+++ b/specs/core/0_fork-choice.md
@@ -251,8 +251,6 @@ def on_attestation(store: Store, attestation: Attestation) -> None:
     # Use GENESIS_EPOCH for previous when genesis to avoid underflow
     previous_epoch = current_epoch - 1 if current_epoch > GENESIS_EPOCH else GENESIS_EPOCH
     assert target.epoch in [current_epoch, previous_epoch]
-    # Cannot calculate the current shuffling if have not seen the target
-    assert target.root in store.blocks
 
     # Attestations target be for a known block. If target block is unknown, delay consideration until the block is found
     assert target.root in store.blocks