fix(consensus): vote extensions verified multiple times

internal/consensus/state_add_vote.go

@@ -1,6 +1,7 @@
 package consensus
 
 import (
+	"bytes"
 	"context"
 	"errors"
 
@@ -238,6 +239,14 @@ func addVoteVerifyVoteExtensionMw(
 				return next(ctx, stateData, vote)
 			}
 
+			// If we already know of this vote, return false to not verify it multiple times
+			existing := stateData.Votes.GetVoteSet(vote.Round, vote.Type).GetByIndex(vote.ValidatorIndex)
+			if existing != nil &&
+				bytes.Equal(existing.BlockSignature, vote.BlockSignature) &&
+				bytes.Equal(existing.VoteExtensions.Fingerprint(), vote.VoteExtensions.Fingerprint()) {
+				return false, nil
+			}
+
 			// The core fields of the vote message were already validated in the
 			// consensus reactor when the vote was received.
 			// Here, we verify the signature of the vote extension included in the vote