diff --git a/beacon-chain/rpc/core/validator.go b/beacon-chain/rpc/core/validator.go
index 7092a6979f7c..9a5663bbfcad 100644
--- a/beacon-chain/rpc/core/validator.go
+++ b/beacon-chain/rpc/core/validator.go
@@ -401,7 +401,19 @@ func (s *Service) GetAttestationData(
 	if err != nil {
 		return nil, &RpcError{Reason: Internal, Err: errors.Wrap(err, "could not get target root")}
 	}
-	justifiedCheckpoint := s.FinalizedFetcher.CurrentJustifiedCheckpt()
+
+	headState, err := s.HeadFetcher.HeadState(ctx)
+	if err != nil {
+		return nil, &RpcError{Reason: Internal, Err: errors.Wrap(err, "could not get head state")}
+	}
+	if coreTime.CurrentEpoch(headState) < slots.ToEpoch(req.Slot) { // Ensure justified checkpoint safety by processing head state across the boundary.
+		headState, err = transition.ProcessSlotsUsingNextSlotCache(ctx, headState, headRoot, req.Slot)
+		if err != nil {
+			return nil, &RpcError{Reason: Internal, Err: errors.Errorf("could not process slots up to %d: %v", req.Slot, err)}
+		}
+	}
+	justifiedCheckpoint := headState.CurrentJustifiedCheckpoint()
+
 	if err = s.AttestationCache.Put(&cache.AttestationConsensusData{
 		Slot:     req.Slot,
 		HeadRoot: headRoot,
diff --git a/beacon-chain/rpc/eth/validator/handlers_test.go b/beacon-chain/rpc/eth/validator/handlers_test.go
index bf41243930a7..178d6fcb0c00 100644
--- a/beacon-chain/rpc/eth/validator/handlers_test.go
+++ b/beacon-chain/rpc/eth/validator/handlers_test.go
@@ -838,10 +838,14 @@ func TestGetAttestationData(t *testing.T) {
 		justifiedRoot, err := justifiedBlock.Block.HashTreeRoot()
 		require.NoError(t, err, "Could not get signing root for justified block")
 		slot := 3*params.BeaconConfig().SlotsPerEpoch + 1
+		beaconState, err := util.NewBeaconState()
+		require.NoError(t, err)
+		require.NoError(t, beaconState.SetSlot(slot))
 		justifiedCheckpoint := &ethpbalpha.Checkpoint{
 			Epoch: 2,
 			Root:  justifiedRoot[:],
 		}
+		require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(justifiedCheckpoint))
 		offset := int64(slot.Mul(params.BeaconConfig().SecondsPerSlot))
 		chain := &mockChain.ChainService{
 			Optimistic:                 false,
@@ -849,6 +853,7 @@ func TestGetAttestationData(t *testing.T) {
 			Root:                       blockRoot[:],
 			CurrentJustifiedCheckPoint: justifiedCheckpoint,
 			TargetRoot:                 blockRoot,
+			State:                      beaconState,
 		}
 
 		s := &Server{
@@ -1076,10 +1081,14 @@ func TestGetAttestationData(t *testing.T) {
 		justifiedRoot, err := justifiedBlock.Block.HashTreeRoot()
 		require.NoError(t, err, "Could not get signing root for justified block")
 
+		beaconState, err := util.NewBeaconState()
+		require.NoError(t, err)
+		require.NoError(t, beaconState.SetSlot(slot))
 		justifiedCheckpt := &ethpbalpha.Checkpoint{
 			Epoch: 0,
 			Root:  justifiedRoot[:],
 		}
+		require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(justifiedCheckpt))
 		require.NoError(t, err)
 		offset := int64(slot.Mul(params.BeaconConfig().SecondsPerSlot))
 		chain := &mockChain.ChainService{
@@ -1087,6 +1096,7 @@ func TestGetAttestationData(t *testing.T) {
 			Genesis:                    time.Now().Add(time.Duration(-1*offset) * time.Second),
 			CurrentJustifiedCheckPoint: justifiedCheckpt,
 			TargetRoot:                 blockRoot,
+			State:                      beaconState,
 		}
 
 		s := &Server{
@@ -1163,17 +1173,24 @@ func TestGetAttestationData(t *testing.T) {
 		require.NoError(t, err, "Could not hash beacon block")
 		justifiedBlockRoot, err := justifiedBlock.Block.HashTreeRoot()
 		require.NoError(t, err, "Could not hash justified block")
+
+		slot := primitives.Slot(10000)
+		beaconState, err := util.NewBeaconState()
+		require.NoError(t, err)
+		require.NoError(t, beaconState.SetSlot(slot))
 		justifiedCheckpt := &ethpbalpha.Checkpoint{
 			Epoch: slots.ToEpoch(1500),
 			Root:  justifiedBlockRoot[:],
 		}
-		slot := primitives.Slot(10000)
+		require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(justifiedCheckpt))
+
 		offset := int64(slot.Mul(params.BeaconConfig().SecondsPerSlot))
 		chain := &mockChain.ChainService{
 			Root:                       blockRoot[:],
 			Genesis:                    time.Now().Add(time.Duration(-1*offset) * time.Second),
 			CurrentJustifiedCheckPoint: justifiedCheckpt,
 			TargetRoot:                 blockRoot,
+			State:                      beaconState,
 		}
 
 		s := &Server{
diff --git a/beacon-chain/rpc/prysm/v1alpha1/validator/attester_mainnet_test.go b/beacon-chain/rpc/prysm/v1alpha1/validator/attester_mainnet_test.go
index 4c177882e5a3..3d05ef48ca80 100644
--- a/beacon-chain/rpc/prysm/v1alpha1/validator/attester_mainnet_test.go
+++ b/beacon-chain/rpc/prysm/v1alpha1/validator/attester_mainnet_test.go
@@ -49,12 +49,16 @@ func TestAttestationDataAtSlot_HandlesFarAwayJustifiedEpoch(t *testing.T) {
 	justifiedBlockRoot, err := justifiedBlock.Block.HashTreeRoot()
 	require.NoError(t, err, "Could not hash justified block")
 
+	slot := primitives.Slot(10000)
+	beaconState, err := util.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, beaconState.SetSlot(slot))
 	justifiedCheckpoint := &ethpb.Checkpoint{
 		Epoch: slots.ToEpoch(1500),
 		Root:  justifiedBlockRoot[:],
 	}
-	require.NoError(t, err)
-	slot := primitives.Slot(10000)
+	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(justifiedCheckpoint))
+
 	offset := int64(slot.Mul(params.BeaconConfig().SecondsPerSlot))
 	attesterServer := &Server{
 		SyncChecker:           &mockSync.Sync{IsSyncing: false},
@@ -62,7 +66,7 @@ func TestAttestationDataAtSlot_HandlesFarAwayJustifiedEpoch(t *testing.T) {
 		TimeFetcher:           &mock.ChainService{Genesis: time.Now().Add(time.Duration(-1*offset) * time.Second)},
 		CoreService: &core.Service{
 			AttestationCache:      cache.NewAttestationCache(),
-			HeadFetcher:           &mock.ChainService{TargetRoot: blockRoot, Root: blockRoot[:]},
+			HeadFetcher:           &mock.ChainService{TargetRoot: blockRoot, Root: blockRoot[:], State: beaconState},
 			GenesisTimeFetcher:    &mock.ChainService{Genesis: time.Now().Add(time.Duration(-1*offset) * time.Second)},
 			FinalizedFetcher:      &mock.ChainService{CurrentJustifiedCheckPoint: justifiedCheckpoint},
 			OptimisticModeFetcher: &mock.ChainService{Optimistic: false},
diff --git a/beacon-chain/rpc/prysm/v1alpha1/validator/attester_test.go b/beacon-chain/rpc/prysm/v1alpha1/validator/attester_test.go
index 53e331deb0b8..e3d10f92ec67 100644
--- a/beacon-chain/rpc/prysm/v1alpha1/validator/attester_test.go
+++ b/beacon-chain/rpc/prysm/v1alpha1/validator/attester_test.go
@@ -102,17 +102,21 @@ func TestGetAttestationData_OK(t *testing.T) {
 	justifiedRoot, err := justifiedBlock.Block.HashTreeRoot()
 	require.NoError(t, err, "Could not get signing root for justified block")
 	slot := 3*params.BeaconConfig().SlotsPerEpoch + 1
+	beaconState, err := util.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, beaconState.SetSlot(slot))
 	justifiedCheckpoint := &ethpb.Checkpoint{
 		Epoch: 2,
 		Root:  justifiedRoot[:],
 	}
+	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(justifiedCheckpoint))
 	offset := int64(slot.Mul(params.BeaconConfig().SecondsPerSlot))
 	attesterServer := &Server{
 		SyncChecker:           &mockSync.Sync{IsSyncing: false},
 		OptimisticModeFetcher: &mock.ChainService{Optimistic: false},
 		TimeFetcher:           &mock.ChainService{Genesis: time.Now().Add(time.Duration(-1*offset) * time.Second)},
 		CoreService: &core.Service{
-			HeadFetcher: &mock.ChainService{TargetRoot: targetRoot, Root: blockRoot[:]},
+			HeadFetcher: &mock.ChainService{TargetRoot: targetRoot, Root: blockRoot[:], State: beaconState},
 			GenesisTimeFetcher: &mock.ChainService{
 				Genesis: time.Now().Add(time.Duration(-1*offset) * time.Second),
 			},
@@ -338,10 +342,15 @@ func TestGetAttestationData_SucceedsInFirstEpoch(t *testing.T) {
 	targetRoot, err := targetBlock.Block.HashTreeRoot()
 	require.NoError(t, err, "Could not get signing root for target block")
 
+	beaconState, err := util.NewBeaconState()
+	require.NoError(t, err)
+	require.NoError(t, beaconState.SetSlot(slot))
 	justifiedCheckpoint := &ethpb.Checkpoint{
 		Epoch: 0,
 		Root:  justifiedRoot[:],
 	}
+	require.NoError(t, beaconState.SetCurrentJustifiedCheckpoint(justifiedCheckpoint))
+
 	offset := int64(slot.Mul(params.BeaconConfig().SecondsPerSlot))
 	attesterServer := &Server{
 		SyncChecker:           &mockSync.Sync{IsSyncing: false},
@@ -350,7 +359,7 @@ func TestGetAttestationData_SucceedsInFirstEpoch(t *testing.T) {
 		CoreService: &core.Service{
 			AttestationCache: cache.NewAttestationCache(),
 			HeadFetcher: &mock.ChainService{
-				TargetRoot: targetRoot, Root: blockRoot[:],
+				TargetRoot: targetRoot, Root: blockRoot[:], State: beaconState,
 			},
 			GenesisTimeFetcher:    &mock.ChainService{Genesis: prysmTime.Now().Add(time.Duration(-1*offset) * time.Second)},
 			FinalizedFetcher:      &mock.ChainService{CurrentJustifiedCheckPoint: justifiedCheckpoint},