diff --git a/eth/api_backend.go b/eth/api_backend.go
index c4e2508a3d..bb83b078a6 100644
--- a/eth/api_backend.go
+++ b/eth/api_backend.go
@@ -456,6 +456,10 @@ func (b *EthAPIBackend) SyncProgress(ctx context.Context) ethereum.SyncProgress
 	return prog
 }
 
+func (b *EthAPIBackend) ConsensusReady() bool {
+	return b.eth.ConsensusReady()
+}
+
 func (b *EthAPIBackend) SuggestGasTipCap(ctx context.Context) (*big.Int, error) {
 	return b.gpo.SuggestTipCap(ctx)
 }
diff --git a/eth/backend.go b/eth/backend.go
index ba9b4d4459..595a2ba54f 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -25,6 +25,7 @@ import (
 	"math/big"
 	"runtime"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/ethereum/go-ethereum/accounts"
@@ -133,6 +134,19 @@ type Ethereum struct {
 	lock sync.RWMutex // Protects the variadic fields (e.g. gas price and etherbase)
 
 	shutdownTracker *shutdowncheck.ShutdownTracker // Tracks if and when the node has shutdown ungracefully
+
+	clContacted atomic.Bool // Set on first Engine API call (newPayload / FCU)
+}
+
+// MarkCLContacted records that the consensus client has driven this node at
+// least once; catalyst calls it from its package and so cannot reach the field
+// directly.
+func (s *Ethereum) MarkCLContacted() { s.clContacted.Store(true) }
+
+// ConsensusReady reports whether eth_syncing should be allowed to return false.
+// True once the consensus client has driven the node at least once.
+func (s *Ethereum) ConsensusReady() bool {
+	return s.clContacted.Load()
 }
 
 // New creates a new Ethereum object (including the initialisation of the common Ethereum object),
diff --git a/eth/catalyst/api.go b/eth/catalyst/api.go
index 46f8cc98fc..f5eec288e8 100644
--- a/eth/catalyst/api.go
+++ b/eth/catalyst/api.go
@@ -257,6 +257,7 @@ func (api *ConsensusAPI) forkchoiceUpdated(ctx context.Context, update engine.Fo
 	}
 	// Stash away the last update to warn the user if the beacon client goes offline
 	api.lastForkchoiceUpdate.Store(time.Now().Unix())
+	api.eth.MarkCLContacted()
 
 	// Check whether we have the block yet in our database or not. If not, we'll
 	// need to either trigger a sync, or to reject this forkchoice update for a
@@ -945,6 +946,7 @@ func (api *ConsensusAPI) newPayload(ctx context.Context, params engine.Executabl
 	}
 	// Stash away the last update to warn the user if the beacon client goes offline
 	api.lastNewPayloadUpdate.Store(time.Now().Unix())
+	api.eth.MarkCLContacted()
 
 	// If we already have the block locally, ignore the entire execution and just
 	// return a fake success.
diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index 2eb4dee3c0..47ba1084fb 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -161,8 +161,10 @@ func (api *EthereumAPI) BaseFee(ctx context.Context) *hexutil.Big {
 func (api *EthereumAPI) Syncing(ctx context.Context) (interface{}, error) {
 	progress := api.b.SyncProgress(ctx)
 
-	// Return not syncing if the synchronisation already completed
-	if progress.Done() {
+	// Don't claim "synced" until the CL has driven us at least once (post-merge
+	// nodes with Engine API attached). Backends without a CL report ready
+	// immediately via ConsensusReady. Refs #33687.
+	if progress.Done() && api.b.ConsensusReady() {
 		return false, nil
 	}
 	// Otherwise gather the block sync stats
diff --git a/internal/ethapi/api_test.go b/internal/ethapi/api_test.go
index 80a9036ecc..a6d4ad7294 100644
--- a/internal/ethapi/api_test.go
+++ b/internal/ethapi/api_test.go
@@ -493,6 +493,7 @@ func newTestBackend(t *testing.T, n int, gspec *core.Genesis, engine consensus.E
 func (b testBackend) SyncProgress(ctx context.Context) ethereum.SyncProgress {
 	return ethereum.SyncProgress{}
 }
+func (b testBackend) ConsensusReady() bool { return true }
 func (b testBackend) SuggestGasTipCap(ctx context.Context) (*big.Int, error) {
 	return big.NewInt(0), nil
 }
diff --git a/internal/ethapi/backend.go b/internal/ethapi/backend.go
index 25f21c65da..8e77661a9e 100644
--- a/internal/ethapi/backend.go
+++ b/internal/ethapi/backend.go
@@ -42,6 +42,7 @@ import (
 type Backend interface {
 	// General Ethereum API
 	SyncProgress(ctx context.Context) ethereum.SyncProgress
+	ConsensusReady() bool
 
 	SuggestGasTipCap(ctx context.Context) (*big.Int, error)
 	FeeHistory(ctx context.Context, blockCount uint64, lastBlock rpc.BlockNumber, rewardPercentiles []float64) (*big.Int, [][]*big.Int, []*big.Int, []float64, []*big.Int, []float64, error)
diff --git a/internal/ethapi/transaction_args_test.go b/internal/ethapi/transaction_args_test.go
index 1d587032bb..377f2d693d 100644
--- a/internal/ethapi/transaction_args_test.go
+++ b/internal/ethapi/transaction_args_test.go
@@ -335,6 +335,7 @@ func (b *backendMock) ChainConfig() *params.ChainConfig { return b.config }
 func (b *backendMock) SyncProgress(ctx context.Context) ethereum.SyncProgress {
 	return ethereum.SyncProgress{}
 }
+func (b *backendMock) ConsensusReady() bool { return true }
 func (b *backendMock) FeeHistory(ctx context.Context, blockCount uint64, lastBlock rpc.BlockNumber, rewardPercentiles []float64) (*big.Int, [][]*big.Int, []*big.Int, []float64, []*big.Int, []float64, error) {
 	return nil, nil, nil, nil, nil, nil, nil
 }