Since punctuation has a specific location it has to appear in (according to UCCA normalization rules, it has to be a child of the lowest common ancestor of its preceding and following terminal), there is no need to make the classifier decide where it should go.
Punctuation should stay in the list of terminals so that the BiLSTM sees it when going over the text, but it should not go in the buffer as nodes.
Since punctuation has a specific location it has to appear in (according to UCCA normalization rules, it has to be a child of the lowest common ancestor of its preceding and following terminal), there is no need to make the classifier decide where it should go.
Punctuation should stay in the list of terminals so that the BiLSTM sees it when going over the text, but it should not go in the buffer as nodes.