I noticed that most of the page numbers on the right hand pages in my score have moved to Inside Edge, although on the Master Default Page, they are set correctly to Outside Edge. What could have caused this? More confusing is that not all the right hand pages have this problem.
You can see on the screenshots that there are small frames for the page numbers on the actual pages but large frames that span the whole page on the masterpages. Could you possibly have changed your masterpages after adding all those text frames in the score?
EDIT: On another look, I see that the right hand page number is actually aligned to the outside edge – of its small frame!
André, when you override an individual page it becomes set - the only thing that can change that page further is if you change it manually.
If you insert a page earlier in the document then the following page numbers will change but the positioning of the frames (on overridden pages) will not.
Incidentally, this is one of those cases where something like AutoHotkey or Keyboard Maestro comes in really handy. I found myself with this situation a couple of weeks back, and on realising that it affected MOST of the pages in a 90 page score, used Pulover’s Macro Creator (a friendly front end for AHK) to “record” me doing the following:
(With the page number frame selected)
- Turn on the left padlock and turn off the right padlock.
- Type 0.35 into the position from left text box in the bottom panel (you know what I mean)
- Hit tab/enter.
Obviously I also did the inverse for the opposite pages (both my lefts and my rights were wrong). Then I selected each incorrectly-positioned page number and hit my shortcut.
So much quicker than doing the same laborious task yourself, repeatedly.
Oh, and in case you’re wondering, no, you can’t select multiple frames on multiple pages and reset them in one go, or I would have done that 
Ah yes, I of course override every page because of the text frames I added to every page, making the Master Pages ineffective that way, AND I added some Front Matter. I will adjust the page numbers manually. Thanks. I have tried KM a couple of times, but cannot get it to work. Too complicated for me. For the couple of things I need to do more often I can do them by hand instead.
I fixed all the pages, was less work than I thought. 120 pages in 5 minutes. I think now also that it’s much better to have the page number on the Paster Pages in a page wide text frame, not only as a little square in a corner of the page the way I believe it’s by defaults because then it’s easier to control the position of a page number in Paragraph settings.
Yes! I guess the default is different because there’s another frame for the header, and selecting frames that are right on top of each other is difficult. Unless you know how…
Love your Paster Page. Made me smile… 
Dear Florian,
The trick to select different objects (when Dorico refuses to change selection) is to use alt-shift-click.
Once the proper frame is selected, pressing enter allows you to edit the text.
Ah yes. Thanks for reminding me, Marc!