Whenever I cite a Nature paper using the cite button on the 2017 wikitext editor, the date gets imported with YYYY-MM, which is not allowed via the MOS and leads to an error. See: https://en.wikipedia.org/wiki/Help_talk:Citation_Style_1#Allow_YYYY-MM_format_for_cite_journal?. This error doesn't occur when using the https://en.wikipedia.org/wiki/Wikipedia:RefToolbar. Could you also display the date February 2020 or simply 2020?
Topic on 2017 wikitext editor/Feedback
The English Wikipedia has decided to reject this class of ISO standards-compliant dates. I find it annoying, too.
Years ago, I heard editors justify this rule because of the fear was that future editors would not be able to tell whether 2001-02 meant two years (2001–2002) or a year and month (February 2001). However, there is no possibility of confusion any source after 2012, and only a tiny fraction of dates from 2000–2011 would be potentially confusing and not banned by the English Wikipedia's MOS.
In the last discussion I had on this, we couldn't even agree about whether the MOS rule applies to what's typed in the wikitext vs what's shown to readers. (For example: So long as the reader sees July 2021, does it matter if I typed |iso-date=2021-07 in wikitext?)