Checkpoint error or bug in rasa?

Dear developers,

I think that there might potentially be a bug with the rasa checkpoint. Created several check points as shown below

Despite having added all appropriate checkpoints, i am getting this error It is also inconsistent, as in anothe test case, when i just shift utter_closing to become part of further_questions and no further questions story, the checkpoint worked. It also worked for some other stories linked to the checkpoint but not for some specific stories even though i have checked and rechecked that there is no error. Thanks!