Reject stale battle save effects

src/game/state/battleSaveState.ts

@@ -163,6 +163,10 @@ export function isValidBattleSaveState(state: unknown, options: BattleSaveValida
     return false;
   }
 
+  if (!areEffectsTargetingLiveUnits(state.battleBuffs, state.battleStatuses, units)) {
+    return false;
+  }
+
   if (
     !isOptionalItemStockRecord(state.itemStocks, options) ||
     !isOptionalBuffArray(state.battleBuffs, options) ||
@@ -282,6 +286,21 @@ function areAttackIntentsTargetingLiveUnits(attackIntents: BattleSaveAttackInten
   return attackIntents.every((intent) => liveUnitIds.has(intent.attackerId) && liveUnitIds.has(intent.targetId));
 }
 
+function areEffectsTargetingLiveUnits(
+  battleBuffs: unknown,
+  battleStatuses: unknown,
+  units: SavedBattleUnitState[]
+) {
+  const liveUnitIds = new Set(units.filter((unit) => unit.hp > 0).map((unit) => unit.id));
+  const buffTargetsAreLive =
+    battleBuffs === undefined ||
+    (Array.isArray(battleBuffs) && battleBuffs.every((buff) => isRecord(buff) && liveUnitIds.has(String(buff.unitId))));
+  const statusTargetsAreLive =
+    battleStatuses === undefined ||
+    (Array.isArray(battleStatuses) && battleStatuses.every((status) => isRecord(status) && liveUnitIds.has(String(status.unitId))));
+  return buffTargetsAreLive && statusTargetsAreLive;
+}
+
 function isSavedBattleUnitState(value: unknown, options: BattleSaveValidationOptions): value is SavedBattleUnitState {
   if (!isRecord(value) || typeof value.id !== 'string' || value.id.length === 0 || !isEquipmentSet(value.equipment, options)) {
     return false;