RTDE cannot write regiters after error

Hello, I wonder if somebody ever met this problem:
I am using RTDE to write some value into registers. However, if a robot error (like a protective stop) occured, and after I push the enable robot button, I can still connect to the robot, but can no more write into registers, the regiester just stuck in values I sent before. I cannot solve this other than restarting the whole system. Does anybody know the reason?