Hello, Bleeding from RCT treated tooth is a very very rare and unusual situation. The most common reason of bleeding while brushing teeth is due to infection in gums (pyorrhoea) or any abscess or ulcer. You might need scaling of your teeth. You will have to go and get it checked to know the exact reason.
Health Tips
Donot brush forcefully especially near gum region. But at the same time, donot avoid brushing due to bleeding.