Пропадают значения свойств в товарах

<?
AddEventHandler("iblock", "OnAfterIBlockElementAdd", "MinMaxSKUPriceUpdate");
AddEventHandler("iblock", "OnBeforeIBlockElementUpdate", "MinMaxSKUPriceUpdate");
 
function MinMaxSKUPriceUpdate(&$arFields){
 
if($arFields['IBLOCK_ID']==2){
   
    $MIN_PRICE=0;
    $MAX_PRICE=0;
 
    $resffer = CIBlockPriceTools::GetOffersArray(
      2, 
      $arFields['ID'], 
      array("NAME"=>"asc"), 
      array('IBLOCK_ID', 'ID', 'CATALOG_GROUP_1'), 
      array(), 
      0, 
      array("BASE"), 
      "N"
   );
   if(is_array($resffer)){
      foreach ($resffer as $key => $value) {
            if($MIN_PRICE==0) $MIN_PRICE=$value['CATALOG_PRICE_1'];
            if($MAX_PRICE==0) $MAX_PRICE=$value['CATALOG_PRICE_1'];
 
            if(!isset($MIN_PRICE)){$MIN_PRICE = $value['CATALOG_PRICE_1'];}
            if(!isset($MAX_PRICE)){$MAX_PRICE = $value['CATALOG_PRICE_1'];}
 
 
            if($MIN_PRICE > $value['CATALOG_PRICE_1']){
               $MIN_PRICE = $value['CATALOG_PRICE_1'];
            }
            if($MAX_PRICE < $value['CATALOG_PRICE_1']){
               $MAX_PRICE = $value['CATALOG_PRICE_1'];
            }
      }
   }
 
   $arPrice = CCatalogProduct::GetOptimalPrice($arFields['ID'], 1, array(1,2,3,4,5,6,7));
      $MIN_PRICE=floatval($MIN_PRICE);
      if($MIN_PRICE=="") $MIN_PRICE=$arPrice["DISCOUNT_PRICE"];
   if($arPrice["DISCOUNT_PRICE"]!="" && $arPrice["DISCOUNT_PRICE"]<$MIN_PRICE){
      $MIN_PRICE=$arPrice["DISCOUNT_PRICE"];
    }
 
 
      $arFields['PROPERTY_VALUES']['MINIMUM_PRICE'] = $MIN_PRICE;
      $arFields['PROPERTY_VALUES']['MAXIMUM_PRICE'] = $MAX_PRICE;
}
   
}
?>