Is there maybe a way we could just have a button on both skins that could switch this?

It happens all the time for me now. I think I've seen this with other sites before, my gut feeling is there's a link floating around somewhere (maybe on google? some forum thread? etc.?) from a mobile or desktop user that has something in the URL that causes the forum software to switch themes when you visit the page.

There is. If you're displaying full site on mobile, scroll to the very bottom of the page (easiest on non-thread pages) and click the big green button.

If you're on mobile skin on desktop, open the 3-line menu in the upper left and select "View Full Site"

It happens to me which I follow links from Google search results which happen to be to the mobile version of FlyerTalk. Sometimes, even a link in a FlyerTalk post will be to the mobile version and mess up the desktop view.

This frequently happens to me with Wikipedia links in Google

Ahhh I think this explains a lot. I actually routinely, instinctively look for that link on most sites, because it does happen quite a lot. There's a bit of an odd issue with the desktop skin, where I suspect on some window sizes/browsers/systems, the link to switch to desktop appears or disappears. For my usual scaling and browser (on desktop), a link only appears if i resize the window so it's narrow, and then I see "View Desktop Site" show up in the hamburger menu.

I also see a "view full site" button in the skin source somewhere, but I didn't immediately figure out how to get it to show up and didn't find it on the page with ctrl+f, but maybe I missed something else.

Do all users understand what the "full site" is? They might see the option but it doesn't click what the option really is?

Perhaps worth considering a wording change for "Switch to Full Site" could be "Switch to desktop site" or if length permits "Switch from mobile to desktop site". Vice versa for the other direction.

To be very clear, there is no button, link, or anything else visible with normal window sizes on any of my desktops (at least for me). There is simply no button unless I resize mobile skin to "smartphone" window sizes. It seems like some sort of bug where the button might not show up in many cases. I am using Chrome and Firefox on Windows on all of my desktop devices and this happens on all of them. I have not had an issue on any of my smartphones.

I have some web design experience so I know how to interpret the source code of the site, and that is where I saw that a developer had intended for a "full site" button to show. Unfortunately, it does not show on any of my systems, and it's more time than I can spend to figure out why. It's getting pretty annoying at this point, so I'm hoping post helps the maintainers resolve the situation.

I recently clicked in from a google search looking for mileage run info, and had my view automatically switched to mobile, but caught the link in action. Of course the reason I do this so routinely is the search feature sometimes just doesn't work well. A search result linked directly to a webpage with the "styleid" explicitly set to mobile view:
This is odd, because why would Google be finding links that explicitly switch the view to mobile and desktop? And then it hit me - ironically, I believe the additional mobile/desktop links that have been plastered on the site (some hidden on certain devices/screen sizes, some shown) are actually causing the problem. Search engines will read all the different links shown on a website unless the links are explicitly marked to not be indexed. At least one of the mobile/desktop view links was inadvertently not marked as such, and thus search engines will actually occasionally randomly follow those "switch view" links (which exists for every single forum post!) and consider that another possible webpage. Unfortunately it's probably too late now to remove all the links Google has crawled in its history - the only real solution is likely to disable the "styleid" key altogether, rename it, and be more careful about any future "switch desktop" or "switch mobile" links in the future.

Separately, regarding the missing buttons, there are web development tools that will easily send you screenshots of websites from a huge variety of platforms, some of them even free, so it may be worth it for one of the maintainers to run one of them and figure out which offending browser/screen/device combinations and causing all the reports of difficulty switching back and forth.

---

Here's what the hamburger menu (this is the actual technical term for the three lines) looks like on all my desktop systems, resized, and not, during a single session:

Related to this, lately a lot of Google search results links that I follow to FT link to the printer friendly version of a page

This happened to me a couple of days ago. I am glad this thread is stuck to the top of the Technical Support forum so I was able to find the link to switch back with ease.

-J.

Very helpful! Thank you. Wasted 10 mins of my life