model parameters of meta-training

[quyouyuan]

Hello, I use reinforcement learning. During the meta training, I will test the model parameters trained every time in the training task, and get the following success rate. In the later stage, the success rate will be zero. Do you think this is correct?Why is it a little high in the early stage and zero in the later stage?
Give the result as follows：

-epoch is: 0, eval success rate is: 0.000
epoch is: 1, eval success rate is: 89.000
epoch is: 2, eval success rate is: 46.000
epoch is: 3, eval success rate is: 40.000
epoch is: 4, eval success rate is: 50.000
epoch is: 5, eval success rate is: 57.000
epoch is: 6, eval success rate is: 70.000
epoch is: 7, eval success rate is: 56.000
epoch is: 8, eval success rate is: 65.000
epoch is: 9, eval success rate is: 79.000
epoch is: 10, eval success rate is: 88.000
epoch is: 11, eval success rate is: 69.000
epoch is: 12, eval success rate is: 89.000
epoch is: 13, eval success rate is: 82.000
epoch is: 14, eval success rate is: 81.000
epoch is: 15, eval success rate is: 77.000
epoch is: 16, eval success rate is: 68.000
epoch is: 17, eval success rate is: 55.000
epoch is: 18, eval success rate is: 45.000
epoch is: 19, eval success rate is: 30.000
epoch is: 20, eval success rate is: 16.000
epoch is: 21, eval success rate is: 24.000
epoch is: 22, eval success rate is: 23.000
epoch is: 23, eval success rate is: 19.000
epoch is: 24, eval success rate is: 1.000
epoch is: 25, eval success rate is: 3.000
epoch is: 26, eval success rate is: 0.000
epoch is: 27, eval success rate is: 0.000
epoch is: 28, eval success rate is: 0.000
epoch is: 29, eval success rate is: 0.000
epoch is: 30, eval success rate is: 0.000
epoch is: 31, eval success rate is: 0.000
epoch is: 32, eval success rate is: 0.000
epoch is: 33, eval success rate is: 0.000
epoch is: 34, eval success rate is: 0.000
epoch is: 35, eval success rate is: 0.000
epoch is: 36, eval success rate is: 0.000
epoch is: 37, eval success rate is: 0.000
epoch is: 38, eval success rate is: 0.000
epoch is: 39, eval success rate is: 0.000
epoch is: 40, eval success rate is: 0.000
epoch is: 41, eval success rate is: 0.000
epoch is: 42, eval success rate is: 0.000
epoch is: 43, eval success rate is: 0.000
epoch is: 44, eval success rate is: 0.000
epoch is: 45, eval success rate is: 0.000
epoch is: 46, eval success rate is: 0.000
epoch is: 47, eval success rate is: 0.000
epoch is: 48, eval success rate is: 0.000
epoch is: 49, eval success rate is: 0.000