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