Training disables if turn of if add method for Agent

Hello! I’ve been following bentrevett’s repo on RL and got a crazy idea.
Having class Agent(nn.Module) implement a method which will do sampling and making log_prob for reinforcement learning. But it ruined everything. It ruins only if I use it for training(where I need gradients), in other places it does’t change anything.

def sample_action(self, state, stoch=True):
    self.__action_pred, value_pred = self.forward(state)
    self.__action_prob = F.softmax(self.__action_pred, dim = -1)
    dist = distributions.Categorical(self.__action_prob)
    if stoch:
        action = dist.sample()
        action = torch.argmax(self.__action_prob, dim = -1)
    return action, value_pred, dist

here is the function that ruins learning.
More, if I even return
self.__action_pred, value_pred = self.forward(state)
learning stops(

You can find problem example here
Dont you know what is this?