The condition was:

 if (m_PreTreatedData->GetFrontTStripNbr(couple[i].X()) == m_PreTreatedData->GetFrontTStripNbr(t) ||
                m_PreTreatedData->GetFrontTDetectorNbr(couple[i].X()) == m_PreTreatedData->GetFrontTDetectorNbr(t))

i.e., if the strip number is the same or the detector number is the same.

This has been modified to:

 if (m_PreTreatedData->GetFrontTStripNbr(couple[i].X()) == m_PreTreatedData->GetFrontTStripNbr(t) &&
                m_PreTreatedData->GetFrontTDetectorNbr(couple[i].X()) == m_PreTreatedData->GetFrontTDetectorNbr(t))

i.e. the strip number and detector number should both be the same.