Here's some reliable steps to reproduce:
- Go to PFWiki on a desktop browser. Log out if logged in.
- Go to a page; let's say Andoran for this example, but any page will do it.
- Does it render with the mobile theme? Purge it. http://pathfinderwiki.com/wiki/Andoran?action=purge
- Confirm that the page renders with the desktop theme by going to the normal, non-purge URL (http://pathfinderwiki.com/wiki/Andoran).
- Go to PFWiki on a mobile browser. Log out if logged in.
- Go to the same page with the normal URL (http://pathfinderwiki.com/wiki/Andoran). It renders with the desktop theme.
- Purge the page. http://pathfinderwiki.com/wiki/Andoran?action=purge
- Confirm that the page renders with the mobile theme (http://pathfinderwiki.com/wiki/Andoran).
- Go to that page on the desktop browser, again while logged out. It renders with the mobile theme.
Some googling suggests that if Extension:MobileFrontend is in use, a workaround might be to redirect mobile visits to a dedicated subdomain, such as m.pathfinderwiki.com, as the cache may not be able to tell mobile and desktop visitors apart even if the Extension can. Disabling the cache may also do the trick, but that's obviously more strenuous on the server.
Just an FYI, I had this happen to me on the front page for the first time in forever yesterday, so even thought its not as frequent, looks like its still happening sometimes
It's likely the upgrade to 1.23 will at least help with this, as it provides links to switch between themes. Not sure if I there's a way to do that in 1.19 in the meantime, but it's worth looking into. Added to my todos.