When you are editing an article the language links from Wikidata are not shown in the sidebar. Local links are shown.
(Reported at https://en.wikipedia.org/wiki/Wikipedia_talk:Wikidata/Archive_1#No_interwiki_links_when_you_are_in_edit_mode%3F)
See Also:
T48488: edit links is shown in page history view (without links)
T63768: "Data item" link in sidebar disappears in classic edit mode