diff --git a/module/data/fields/action/damageField.mjs b/module/data/fields/action/damageField.mjs
index 56eb51e5..d0ce0a80 100644
--- a/module/data/fields/action/damageField.mjs
+++ b/module/data/fields/action/damageField.mjs
@@ -109,7 +109,7 @@ export default class DamageField extends fields.SchemaField {
                 );
             else {
                 const configDamage = foundry.utils.deepClone(config.damage);
-                const hpDamageMultiplier = config.actionActor?.system.rules.attack.damage.hpDamageMultiplier ?? 1;
+                const hpDamageMultiplier = config.actionActor?.system.rules?.attack.damage.hpDamageMultiplier ?? 1;
                 const hpDamageTakenMultiplier = actor.system.rules.attack.damage.hpDamageTakenMultiplier;
                 if (configDamage.hitPoints) {
                     for (const part of configDamage.hitPoints.parts) {