There’s just too many weird things that happen for it to be normal. At least in the opinion of my Finale refugee self.
I’m a Finale refugee myself. Can you be more specific – give an example? While I mostly use it on a Mac Mini, I haven’t found the iPad version to be glitchy. (Although it is easier the navigate with the keyboard attached!)
— Jim
Do you use a mouse? I think most of the problems come from trying to move things with touch, like in engrave, everything wants to move instead of the object. But then once in a while it will move, even though I’ve done nothing different. Also some of the drop down menus like in the three dot menu (whatever it’s called) in the top right it is very hard to stop it where you want it anywhere below “flip”. It just keeps bouncing back up to the top. Like if I’m trying to get to “noteheads” or something.
In my experience, no, it’s not.
I don’t think I’ve tried a mouse — and, yes, my fat fingers are a bit troublesome to control! I usually zoom in to make it easier. Have you tried a pen (some 3rd party pens are more reasonable than the official Apple pen)?
Dorico has very robust spacing algorithms. If you have your options set properly to your liking, you will have little need to move things — unlike Finale!, 
— Jim
Many times I’m using iPad Dorico during my morning commute, and I find that an Apple Pencil makes selecting things easier. I’ve also used the iPad with an Apple Magic Keyboard and Mouse, and it’s just like working on the desktop.
But things randomly move. They start out in the right spot, like say I write in r.s. (Rim shot) using the text popover, and later I notice it’s way out of place. Then I can’t get it to go back where it was. But other texts I wrote in the same way don’t get the wanderlust and stay at home.
That could be due to the collision avoidance. The settings are in the Layout options. It might be due to something else — if you can upload your project (or a section of the problem area) someone more expert than me can take a look. Did you get the license to use Engrave Mode?
If you can provide an example document where this happens, then that might help to pinpoint the cause.
The notation “engine” in Dorico for iPad is essentially the same as the desktop versions, so things shouldn’t move about by themselves.
Could it be something like you moving an item “Globally” (in the Preference panel), so that it moves in every layout?