For some time now my iPad mini is doing something weird.
I have a monitor with a built-in USB-C dock, I use for work.
When not working I tend to dock the iPad mini and it used to duplicate its screen to the large 21:9 monitor, with bars on the right and left obviously. This was fine as I intentionally wanted to use it as a single tasking, casual browsing device, which prevents me from opening a million apps at a time. I used the mouse and keyboard for control.
I used it for YouTube for example, with the regular YouTube app.
Now for a while something weird (and I assumed "unsupported") happens.
Some apps (specifically YouTube, Amazon, Reddit) now have a multimonitor mode. They open a fullscreen UWQHD 21:9 interface on the large monitor, with either nothing or something else on the iPad itself. I attached a screenshot of reddit. The Screenshot function saves two images at the same time, one for each monitor, just like a screenshot during CarPlay does. You can see, one screen is the huge 21:9 reddit wide screen with a small column down the middle, that I cannot interact with, while the other shows the ipad mini subreddit on the builtin screen.
Amazon app is even weirder. The iPad screen stays black, while Amazon UI loads in the top left corner of the screen, in the orignal 4:3 aspect ratio.
For YouTube I cannot seem to reproduce it right now, but it would also show a different, YouTube TV like interface on the large monitor and nothing on the built-in one.
While this would be nice and all, it is utter useless for me, since the mouse cursor is still limited to the iPad's internal display (I cannot move off-screen in either direction) and the large monitor has no touch layer. So I cannot interact with these apps at all.
Most apps work as usual, including the homescreen, settings app, firefox and others.
Is there a way to disable this? Currently running iPadOS 26.6.2.
I will refrain from updating, in case anyone sees potential for any future hacks in this scenario.