diff --git a/stackit/internal/services/observability/alertgroup/resource.go b/stackit/internal/services/observability/alertgroup/resource.go
index 953c55492..fc1cba468 100644
--- a/stackit/internal/services/observability/alertgroup/resource.go
+++ b/stackit/internal/services/observability/alertgroup/resource.go
@@ -118,7 +118,7 @@ func (a *alertGroupResource) ValidateConfig(ctx context.Context, req resource.Va
 	}
 
 	rules := &[]rule{}
-	diags := resourceModel.Rules.ElementsAs(ctx, rules, false)
+	diags := resourceModel.Rules.ElementsAs(ctx, rules, true)
 	resp.Diagnostics.Append(diags...)
 	if resp.Diagnostics.HasError() {
 		return