I found a solution, but it isn’t that convenient (and even more important will not give the result you want if you remove the 1st unmanipulated citation). For some reason (which you found) if you try to apply the no year to the Author (Year) formatted citation, it reverts to the (Author) not year, and not the Author (no year). But if you instead unformat the citations, and remove the year from the temporary citation, it will work. It just doesn’t appear to be automatable. Great request.
If you want to avoid the extra space which would now appear after the author in the APA style as it comes out of the box, all spaces are link adjacent except for the one in “Cited Pages”. – or you can remove the space before the trailing word (“said that” in the below).
Author| (Year|, p.^pp. Cited Pages|)|
{Ellis, 1990 #1431@@author-year} said this and then {Ellis, #1431@@author-year} said that.
Just to mention, that for most publishers I deal with, they have the tools to correct these kind of indiosyncracies in-house. I focus on making our manuscript of interest to the community (and hopefully editor) and have never had a copy editor then reject a paper because the hard to achieve formating of citations/references didn’t exactly match the style manual.