On the bottom of page ten of the following paper on probabilistic reinforcement learning, there are 3 equations where is author manipulates the policy gradient $$\nabla_\theta J(\theta)$$.
$$\nabla_\theta log\ q_\theta (a_t|s_t) (\sum_{t'=t}^T b(s_{t'})) = 0$$ or $$E_{(s_t,a_t) ~ q(s_t,a_t)}[\nabla_\theta log\ q_\theta (a_t|s_t) (\sum_{t'=t}^T b(s_{t'}))] = 0$$