[Possible Bug?] Should is_level_order_list always have atleast one element as 1?

[awasthiabhijeet]

Hi @OhadRubin ,

Regarding is_levelorder_list defined at the following line: https://github.com/OhadRubin/SmBop/blob/e7a6fce7af5aa5545bd3cfca6c4c4dbef610cd6b/smbop/models/smbop.py#L682

For debugging, I was feeding the validation dataset while training the SmBOP model. I see that is_levelorder_list contains all zero elements for some examples at some decoding steps. Is this expected? As per my understanding, is_levelorder_list should have at least 1 non-zero element for each example, at each decoding step.