Hi! It looks like you’re running into a bug. When the footnotes are turned off via the “Notes” tab in the prototype sidebar in the browser, they should stay off for all widgets; the fact that repeaters are turning their own back on seems buggy, so I’ve gone ahead and filed this with QA for further investigation. We’ll update this thread with any additional information as it comes up, but otherwise please keep an eye on the 8 beta channel updates thread for posts about new bug fixes.
In the meantime, if you need the footnotes to remain hidden while working on your repeater, you can go to “Publish > Generate HTML > Widget Notes” and disable the “Include Widget Notes Footnotes” checkbox. This will prevent any footnotes from showing on widgets in the browser, but your widget notes will still be viewable in the “Notes” tab of the sidebar if you leave “Include Widget Notes in Sidebar” enabled. Hopefully that helps a bit!