diff --git a/bundle/config/validate/interpolation_in_auth_config.go b/bundle/config/validate/interpolation_in_auth_config.go
index 83d6c6ae14..1a5b64a268 100644
--- a/bundle/config/validate/interpolation_in_auth_config.go
+++ b/bundle/config/validate/interpolation_in_auth_config.go
@@ -24,7 +24,10 @@ func (f *noInterpolationInAuthConfig) Name() string {
 func (f *noInterpolationInAuthConfig) Apply(ctx context.Context, b *bundle.Bundle) diag.Diagnostics {
 	authFields := []string{
 		// Generic attributes.
-		"host", "profile", "auth_type", "metadata_service_url",
+		"host",
+		"profile",
+		"auth_type",
+		"metadata_service_url",
 
 		// OAuth specific attributes.
 		"client_id",
@@ -33,8 +36,12 @@ func (f *noInterpolationInAuthConfig) Apply(ctx context.Context, b *bundle.Bundl
 		"google_service_account",
 
 		// Azure specific attributes.
-		"azure_resource_id", "azure_use_msi", "azure_client_id", "azure_tenant_id",
-		"azure_environment", "azure_login_app_id",
+		"azure_resource_id",
+		"azure_use_msi",
+		"azure_client_id",
+		"azure_tenant_id",
+		"azure_environment",
+		"azure_login_app_id",
 	}
 
 	diags := diag.Diagnostics{}
@@ -49,12 +56,11 @@ func (f *noInterpolationInAuthConfig) Apply(ctx context.Context, b *bundle.Bundl
 			return diag.FromErr(err)
 		}
 
-		if v.Kind() == dyn.KindInvalid || v.Kind() == dyn.KindNil {
+		vv, ok := v.AsString()
+		if !ok {
 			continue
 		}
 
-		vv := v.MustString()
-
 		// Check if the field contains interpolation.
 		if dynvar.ContainsVariableReference(vv) {
 			envVar, ok := auth.GetEnvFor(fieldName)