Re: Point of wrong window used in read-from-minibuffer?

[Richard Stallman]

    As I said, I agree with the general idea that save-window-excursion
    shouldn't affect point, but I indeed think it's more important that it
    shouldn't cause any window's cursor to move.

    Copying the value of one window's point to another window's point is (to me)
    always a bug.

    So, yes, I really think it should be changed.  I doubt it's risky, but
    there's no hurry, so we can keep it for post-22.

I am sure it is risky.  There is, or was, code that depended on the
precise details of this behavior.

Perhaps none will break with the specific change that you have in
mind.  Or perhaps yes some will break.  We don't know--so it is risky.