diff --git a/go/lib/infra/modules/trust/internal/metrics/metrics.go b/go/lib/infra/modules/trust/internal/metrics/metrics.go
index 7f2c14534d..e414ae21f5 100644
--- a/go/lib/infra/modules/trust/internal/metrics/metrics.go
+++ b/go/lib/infra/modules/trust/internal/metrics/metrics.go
@@ -41,15 +41,16 @@ const (
 	OkExists    = "ok_exists"
 	OkInserted  = "ok_inserted"
 
-	ErrDB       = prom.ErrDB
-	ErrDenied   = "err_denied"
-	ErrInternal = prom.ErrInternal
-	ErrTransmit = "err_transmit"
-	ErrTimeout  = prom.ErrTimeout
-	ErrValidate = prom.ErrValidate
-	ErrVerify   = prom.ErrVerify
-	ErrTRC      = "err_trc"
-	ErrNotFound = "err_not_found"
+	ErrDB           = prom.ErrDB
+	ErrDenied       = "err_denied"
+	ErrInternal     = prom.ErrInternal
+	ErrTransmit     = "err_transmit"
+	ErrTimeout      = prom.ErrTimeout
+	ErrValidate     = prom.ErrValidate
+	ErrVerify       = prom.ErrVerify
+	ErrTRC          = "err_trc"
+	ErrNotFound     = "err_not_found"
+	ErrNotFoundAuth = "err_not_found_auth"
 )
 
 var (
diff --git a/go/lib/infra/modules/trust/trust.go b/go/lib/infra/modules/trust/trust.go
index 18fca45e65..430a8be1e9 100644
--- a/go/lib/infra/modules/trust/trust.go
+++ b/go/lib/infra/modules/trust/trust.go
@@ -216,6 +216,16 @@ func (store *Store) getTRC(ctx context.Context, isd addr.ISD, version scrypto.Ve
 		metrics.Store.Lookup(l.WithResult(metrics.OkCached)).Inc()
 		return trcObj, nil
 	}
+	if store.config.ServiceType == proto.ServiceType_cs &&
+		store.config.TopoProvider.Get().Core && store.ia.I == isd {
+		// Core CS can't find TRC for its own ISD
+
+		metrics.Store.Lookup(l.WithResult(metrics.ErrNotFoundAuth)).Inc()
+		// XXX(kormat): Wrap ErrMissingAuthoritative with ErrNotFoundLocally to
+		// simplify logic in LoadAuthoritativeTRC
+		return nil, serrors.Wrap(ErrMissingAuthoritative, ErrNotFoundLocally,
+			"isd", isd, "version", version, "client", client)
+	}
 	if opts.LocalOnly {
 		metrics.Store.Lookup(l.WithResult(metrics.ErrNotFound)).Inc()
 		return nil, serrors.WithCtx(ErrNotFoundLocally, "isd", isd, "version", version,
@@ -364,9 +374,21 @@ func (store *Store) getChain(ctx context.Context, ia addr.IA, version scrypto.Ve
 		metrics.Store.Lookup(l.WithResult(metrics.OkCached)).Inc()
 		return chain, nil
 	}
-	if store.config.MustHaveLocalChain && store.ia.Equal(ia) {
-		metrics.Store.Lookup(l).Inc()
-		return nil, serrors.WithCtx(ErrMissingAuthoritative, "requested_ia", ia)
+	isCS := store.config.ServiceType == proto.ServiceType_cs
+	isCore := store.config.TopoProvider.Get().Core
+	if (isCS && store.ia.Equal(ia)) ||
+		(isCS && isCore && store.ia.I == ia.I) ||
+		(store.config.MustHaveLocalChain && store.ia.Equal(ia) && version.IsLatest()) {
+		// Either:
+		// - CS can't find a cert for its own AS
+		// or
+		// - Core CS can't find cert for AS in own ISD
+		// or
+		// - Infra service doesn't have any version of its own cert
+
+		metrics.Store.Lookup(l.WithResult(metrics.ErrNotFoundAuth)).Inc()
+		return nil, serrors.WithCtx(ErrMissingAuthoritative, "ia", ia, "version", version,
+			"client", client)
 	}
 	// Chain not found, so we'll need to fetch one. First, fetch the TRC we'll
 	// need during certificate chain validation.
@@ -380,7 +402,8 @@ func (store *Store) getChain(ctx context.Context, ia addr.IA, version scrypto.Ve
 	}
 	if opts.LocalOnly {
 		metrics.Store.Lookup(l.WithResult(metrics.ErrNotFound)).Inc()
-		return nil, serrors.WithCtx(ErrNotFoundLocally, "ia", ia)
+		return nil, serrors.WithCtx(ErrNotFoundLocally, "ia", ia, "version", version,
+			"client", client)
 	}
 	if opts.Server == nil {
 		var err error
diff --git a/go/lib/scrypto/version.go b/go/lib/scrypto/version.go
index 6d3d5ee558..30fac9029c 100644
--- a/go/lib/scrypto/version.go
+++ b/go/lib/scrypto/version.go
@@ -30,6 +30,11 @@ var _ json.Marshaler = (*Version)(nil)
 // marshalled/unmarshalled to/from LatestVer.
 type Version uint64
 
+// IsLatest checks if the value is LatestVer
+func (v Version) IsLatest() bool {
+	return uint64(v) == LatestVer
+}
+
 // UnmarshalJSON checks that the value is not LatestVer.
 func (v *Version) UnmarshalJSON(b []byte) error {
 	parsed, err := strconv.ParseUint(string(b), 10, 64)