The autonym of the Iñupiaq language has been written in MediaWiki as "Iñupiak", with a "k", for pretty much as long as I can dig back in the Git version history.

User:Naulagmi on the English Wikipedia pointed out that this spelling is wrong. I verified, and the report is correct. It is not written with a k anywhere, and the suggested spelling "Iñupiatun" appears in multiple other sources:

• Ethnologue
• https://www.inupiaqonline.com/
• https://ilisaqativut.org/ (as the language selector at the top of the page, so it's the most relevant example)
• Facebook's language selector (you don't even need an account—simply go to the log-in page and try selecting a language by clicking the "+" at the bottom of the page)