diff --git a/chain/gen/gen.go b/chain/gen/gen.go
index f0e884073..6d891f260 100644
--- a/chain/gen/gen.go
+++ b/chain/gen/gen.go
@@ -362,7 +362,7 @@ func (cg *ChainGen) nextBlockProof(ctx context.Context, pts *types.TipSet, m add
 		rbase = entries[len(entries)-1]
 	}
 
-	eproof, err := IsRoundWinner(ctx, pts, round, m, rbase, mbi, mc)
+	eproof, err := IsRoundWinner(ctx, round, m, rbase, mbi, mc)
 	if err != nil {
 		return nil, nil, nil, xerrors.Errorf("checking round winner failed: %w", err)
 	}
@@ -639,7 +639,7 @@ func (wpp *wppProvider) ComputeProof(context.Context, []proof7.ExtendedSectorInf
 	return ValidWpostForTesting, nil
 }
 
-func IsRoundWinner(ctx context.Context, ts *types.TipSet, round abi.ChainEpoch,
+func IsRoundWinner(ctx context.Context, round abi.ChainEpoch,
 	miner address.Address, brand types.BeaconEntry, mbi *api.MiningBaseInfo, a MiningCheckAPI) (*types.ElectionProof, error) {
 
 	buf := new(bytes.Buffer)
diff --git a/cmd/lotus-shed/election.go b/cmd/lotus-shed/election.go
index 7ac74de48..23c533c31 100644
--- a/cmd/lotus-shed/election.go
+++ b/cmd/lotus-shed/election.go
@@ -219,7 +219,7 @@ func backTestWinner(ctx context.Context, miner address.Address, round abi.ChainE
 		brand = bvals[len(bvals)-1]
 	}
 
-	winner, err := gen.IsRoundWinner(ctx, ts, round, miner, brand, mbi, api)
+	winner, err := gen.IsRoundWinner(ctx, round, miner, brand, mbi, api)
 	if err != nil {
 		return nil, xerrors.Errorf("failed to check if we win next round: %w", err)
 	}
diff --git a/miner/miner.go b/miner/miner.go
index 9281854d7..b6285eda6 100644
--- a/miner/miner.go
+++ b/miner/miner.go
@@ -507,13 +507,13 @@ func (m *Miner) mineOne(ctx context.Context, base *MiningBase) (minedBlock *type
 		rbase = bvals[len(bvals)-1]
 	}
 
-	ticket, err := m.computeTicket(ctx, &rbase, base, mbi)
+	ticket, err := m.computeTicket(ctx, &rbase, round, base.TipSet.MinTicket(), mbi)
 	if err != nil {
 		err = xerrors.Errorf("scratching ticket failed: %w", err)
 		return nil, err
 	}
 
-	winner, err = gen.IsRoundWinner(ctx, base.TipSet, round, m.address, rbase, mbi, m.api)
+	winner, err = gen.IsRoundWinner(ctx, round, m.address, rbase, mbi, m.api)
 	if err != nil {
 		err = xerrors.Errorf("failed to check if we win next round: %w", err)
 		return nil, err
@@ -589,15 +589,14 @@ func (m *Miner) mineOne(ctx context.Context, base *MiningBase) (minedBlock *type
 	return minedBlock, nil
 }
 
-func (m *Miner) computeTicket(ctx context.Context, brand *types.BeaconEntry, base *MiningBase, mbi *api.MiningBaseInfo) (*types.Ticket, error) {
+func (m *Miner) computeTicket(ctx context.Context, brand *types.BeaconEntry, round abi.ChainEpoch, chainRand *types.Ticket, mbi *api.MiningBaseInfo) (*types.Ticket, error) {
 	buf := new(bytes.Buffer)
 	if err := m.address.MarshalCBOR(buf); err != nil {
 		return nil, xerrors.Errorf("failed to marshal address to cbor: %w", err)
 	}
 
-	round := base.TipSet.Height() + base.NullRounds + 1
 	if round > build.UpgradeSmokeHeight {
-		buf.Write(base.TipSet.MinTicket().VRFProof)
+		buf.Write(chainRand.VRFProof)
 	}
 
 	input, err := lrand.DrawRandomness(brand.Data, crypto.DomainSeparationTag_TicketProduction, round-build.TicketRandomnessLookback, buf.Bytes())