diff --git a/app/models/concerns/foreman_resource_quota/host_managed_extensions.rb b/app/models/concerns/foreman_resource_quota/host_managed_extensions.rb
index 3d9793f..a52a78b 100644
--- a/app/models/concerns/foreman_resource_quota/host_managed_extensions.rb
+++ b/app/models/concerns/foreman_resource_quota/host_managed_extensions.rb
@@ -19,7 +19,7 @@ module HostManagedExtensions
 
       # A host shall always have a .host_resources attribute
       before_validation :build_host_resources, unless: -> { host_resources.present? }
-      after_save :save_host_resources, if: -> { host_resources.changed? }
+      after_save :save_host_resources, if: -> { host_resources&.changed? }
     end
 
     def verify_resource_quota