Merge branch '21.xForATR-20569' into '21.0'

Bug fix for incorrect BCID from L1MUEndcap to MuCTPI in MC for 21.X (ATR-20569)

See merge request atlas/athena!28173

Trigger/TrigT1/TrigT1TGC/src/LVL1TGCTrigger.cxx

@@ -621,7 +621,10 @@ void LVL1TGCTrigger::FillSectorLogicData(LVL1MUONIF::Lvl1MuSectorLogicData *slda
   int Zdir= (subsystem==LVL1MUONIF::Lvl1MuCTPIInput::idSideA() ? 1 : -1);
 
   sldata->clear2candidatesInSector();// for temporary
-  sldata->bcid(0);
+
+  const int muctpiBcId_offset = TgcDigit::BC_CURRENT;
+  sldata->bcid(m_bctagInProcess - muctpiBcId_offset);
+
   if ((selectorOut->getNCandidate()) >= 1) {
     sldata->roi(0,((selectorOut->getR(0))<<2)+(selectorOut->getPhi(0)));
     //      ovl --> veto