The asset needs not be selected because the default asset is then used. A test script:

Code
void run()
{
   set(PLOTNOW);
   StartDate = 20210102;
   EndDate = 20210110;
   BarPeriod = 15;
   LookBack = 0;
   setf(BarMode,BR_FLAT|BR_ASSET); 

   asset("EUR/USD");
   AssetMarketZone = EST;
   AssetMarketStart = 930;
   AssetMarketEnd = 1630;
   if(is(NOSHIFT))
     plot("Mkt closed",1,NEW|LINE,RED);
}


Also check the exe file date of your beta version. If you downloaded it last weekend, download it again. There was a faulty version on Friday, although it had probably no effect on BR_ASSET.