EndNote needs an Author ID field, AUID- in medline format. The NIH is now going to require an ORCID ID for all submissions starting FY 2020. The information is in the medline download file from pubmed, but the NIH import filter in EndNote does not even have a line for it, so completely ignores it. The notice from the NIH is here: https://grants.nih.gov/grants/guide/notice-files/NOT-OD-19-109.html.
UPDATE: I just noticed, while I was editing the import filter, that the ORCID ID in the AUID field is represented in different ways. Sometimes it is preceeded by AUID- ORCID:, other times it is preceeded by either AUID- ORCID: http://orcid.org/, or AUID- ORCID: https://orcid.org/ (http vs https) . I believe there needs to be some standardization.