Even with the Scrivener App full screen, if Windowed Apps is turned on the Find and Replace dialog process opens, shows on screen, then in seconds dismisses itself. It is fully reproducible. Please see the attached screen recording and duplicate it yourself. A bug fix release is sorely needed. Little things like this make authors unease about losing text or being unable to work. The only suitable workaround is turn off all Windowing, but that causes other usability issue with other apps on the machine.
PS: I have also submitted feedback to Apple, in case it is only an iPadOS issue. It is issue that existed all through the beta release period when developers should have seen this and created new versions. Expect to be contacted.
Thanks for the report, there are a few weird things going on here when one has an external keyboard in use (at least it seems more stable without that). I’ll get them all written up together as I feel they are at least interfering with each other (the large black bar at the bottom of the screen, for instance).
It looks to me as though all (or most) can be avoided by disabling the auxiliary keyboard row, which is the button with four dots and an arrow pointing up to it, on the right side of the standard Apple floating widget thing. So that’s your workaround for now, just toggle that on and off more as needed than always having it on.
It’s what you’re supposed to do in theory, but you have no idea how much time was spent just trying to get the Mac fixed (time that is still being spent cleaning up their mess). We’ll get to iOS, but we can’t do everything at once.