Apple’s Texttools->Proofread does not work as described in Apple’s doc when invoked in Scrivener. Fortunately it also does not work properly in Apple’s Pages, but does work properly in Apple’s Mail app. Because of this, I think this means that Apple changed or added the ways proofread-ing can be invoked or something. So I don’t think this is a ‘bug’ so much as a disconnection between old and new functionality.
Details: currently Scrivener and Apple’s Pages display only three choices when proofread is selected within Apple’s texttools: Replace, Copy, an icon which links to a bug report window. (see screenshot below)
The current Apple doc states that we should be able to sequence through the suggested changes, which is what happens when texttools->proofread is chosen on a selection when composing an email in Mail.
FYI own documentation on what to expect is in §20.3.5, Editing with Apple’s AI Tools, in the user manual PDF.
What you are seeing is how it works with the full text engine. For whatever reason they did not bother to implement the inline, or iterative, interface in it. What you describe is only available with the newer one that offers a subset of features. You can see the swap happen right in front of you in fact, by pasting your text into TextEdit and trying from there. You’ll get the iterative interface like in Mail, because it uses the basic text engine by default. Now select some text and have Writing Tools turn it into a table, and try again (even a small amount of text that doesn’t include the table). It swapped to the more powerful text engine in the background, and thus to the same thing you see Scrivener using.
Clearly they didn’t have time to finish this (I think the whole thing is still marked as beta), or perhaps think through how weird it is to use a tool to modify the text in such a way that the whole tool starts working differently after you use it. So hopefully there are fewer rough edges like this in the future.
Meanwhile, use Snapshots if you want to see a marked up comparison of before/after.
It swapped to the more powerful text engine in the background, and thus to the same thing you see Scrivener using.