In the top example, the NMT seq2seq model incorrectly aligns the target side end of sentence mark eos to 下旬/late with a high attention weight (0.80 in this example) due to the failure of appropriately capturing the similarity, or the lack of it, between the source word 下旬/late and the target eos.
the most appropriate source words are selected according to their attention weights and they are made to more closely interact with target hidden states.