The link to "Guidelines for user pages" in the mobile start module leads to desktop version of the Wikipedia:User_pages, Should link to mobile version of the page instead.
@SBisson I reported it, and it's still happening on Safari iOS 10. However I can't reproduce in any other version of Safari and Safari iOS.
Here is the console output
Failed to set referrer policy: The value 'origin-when-crossorigin' is not one of 'no-referrer', 'origin', 'no-referrer-when-downgrade', or 'unsafe-url'. Defaulting to 'no-referrer'. Wikipedia:User_pages:22
Failed to set referrer policy: The value 'origin-when-crossorigin' is not one of 'no-referrer', 'origin', 'no-referrer-when-downgrade', or 'unsafe-url'. Defaulting to 'no-referrer'. Wikipedia:User_pages:23
Correction: we tested it again and what really fixes it is not the patch but using the browser's incognito mode.
I think this situation can happen in beta but not in production.
In beta, the link navigates between 2 different sites. You start on beta enwiki and land on production enwiki where the real userpage guidelines are. If you had previously forced enwiki to be in desktop mode using the "desktop" link at the bottom of the page, it is going to render in desktop mode, even if you are coming from enwiki beta in mobile mode.
In production, the link always navigate to the same site. If you are looking at the homepage in kowiki, the link will redirect you to the userpage guidelines on kowiki, keeping the same mobile mode.
The intermediate step on wikidata doesn't seem to matter. I have tried forcing wikidata to desktop and going through it on mobile still works.
I just tried this from my phone in Czech Wikipedia, and the link opened the desktop version. See this video: https://drive.google.com/file/d/1YhvySOw8R04IWJOwSV4xyFiJDqJygehC/view
This is an iPhone 6S with iOS 12.2 and Safari 12. Not in private browsing mode. Please let me know if any other details would be helpful.
My testing verifies what @SBisson wrote in the following comment:
@MMiller_WMF - the link to the video is marked as unavailable. Moving to your column so that you can check the fix additionally; it could be some you specific browser setting (or some other settings) that make the link go to the page in desktop mode.