Anyone on iPhone 6s Plus notice that the screen will rotate to landscape and lock. Rotating the phone does not return it to portrait?
screen rotation
Yes! The same thing happens to me. I solved it doing a hard reset.
and also setup that not rotate The screen any more. (Temporarily until this bug is resolved)
This is happen a lot where the rotation appear to get stuck.
Definitely 'a thing.' 6S+ doing this multiple times (since 10b1). As suggested, a hard-reset will clear it, for a while. Also found that closing the jammed app (Safari, or whatever), doing something else, then coming back ten minutes later and the issue often clears itself. On one occasion, my 6S+ Home Screen managed to end up in Landscape after closing an app that was locked in Landscape.