diff --git a/core/bcast/bcast.go b/core/bcast/bcast.go
index bada505eb..2b73d83ef 100644
--- a/core/bcast/bcast.go
+++ b/core/bcast/bcast.go
@@ -82,9 +82,8 @@ func (b Broadcaster) Broadcast(ctx context.Context, duty core.Duty,
 		}
 
 		err = b.eth2Cl.SubmitAttestations(ctx, []*eth2p0.Attestation{&att.Attestation})
-		if err != nil && (strings.Contains(err.Error(), "PriorAttestationKnown") ||
-			strings.Contains(err.Error(), "No peers on libp2p topic")) {
-			// Lighthouse and Nimbus aren't idempotent, so just swallow this non-issue.
+		if err != nil && strings.Contains(err.Error(), "PriorAttestationKnown") {
+			// Lighthouse isn't idempotent, so just swallow this non-issue.
 			// See reference github.com/attestantio/go-eth2-client@v0.11.7/multi/submitattestations.go:38
 			err = nil
 		}
diff --git a/core/bcast/bcast_test.go b/core/bcast/bcast_test.go
index 2f5a56a44..fd0eff062 100644
--- a/core/bcast/bcast_test.go
+++ b/core/bcast/bcast_test.go
@@ -39,19 +39,16 @@ func TestBroadcastAttestation(t *testing.T) {
 
 	aggData := core.Attestation{Attestation: *testutil.RandomAttestation()}
 
-	// Assert output and return lighthouse and nimbus known error on duplicates
+	// Assert output and return lighthouse known error on duplicates
 	var submitted int
 	mock.SubmitAttestationsFunc = func(ctx context.Context, attestations []*eth2p0.Attestation) error {
 		require.Len(t, attestations, 1)
 		require.Equal(t, aggData.Attestation, *attestations[0])
 
 		submitted++
-		if submitted > 2 {
+		if submitted > 1 {
 			// Non-idempotent error returned by lighthouse but swallowed by bcast.
 			return errors.New("Verification: PriorAttestationKnown")
-		} else if submitted > 1 {
-			// Non-idempotent error returned by nimbus but swallowed by bcast.
-			return errors.New(`"message":"No peers on libp2p topic"`)
 		}
 
 		return nil
@@ -64,8 +61,6 @@ func TestBroadcastAttestation(t *testing.T) {
 	require.NoError(t, err)
 	err = bcaster.Broadcast(ctx, core.Duty{Type: core.DutyAttester}, "", aggData)
 	require.NoError(t, err)
-	err = bcaster.Broadcast(ctx, core.Duty{Type: core.DutyAttester}, "", aggData)
-	require.NoError(t, err)
 }
 
 func TestBroadcastBeaconBlock(t *testing.T) {