What you heard is wrong. A person who is attached with tabligh he may go for bai’ah from any Shaikh, both have their own benefits. Under the heading of ‘Zikr’ out of six practices of tabligh it is taught that if someone is murid of any Shaikh then he should regularly follow the wird and wazaif given by him.
Allah (Subhana Wa Ta’ala) knows Best
Darul Uloom Deoband