Forgot atah chonantanu in maariv, but have to say tashlumin

Question

If someone doesn't daven shemoneh esrei for certain reasons, he is able to make it up by davening two shemoneh esreis at the next davening ('tashlumin). The second one is the exact same as the first, except in the case of tashlumin motzei Shabbat, where atah chonantanu is not said the second time.

In an ordinary case, if someone forgets atah chonantanu, they don't repeat shemoneh esrei, because they can just say havdalah later.

So, here, what if someone forgets mincha Shabbat afternoon and has to say tashlumin at maariv. Then, they forgot atah chonantanu in the first (maariv) shemoneh esrei. Should they say it in the tashlumin (mincha) shemoneh esrei, even though it wouldn't normally be said then?

Answer 1

The basic rule by tashlumin is that for all make-up prayers, the first prayer is the current one and the make-up is said afterwards. If this order is switched, the first prayer is invalid (S.A. O.C. 108:1-2).

108:2

טעה ולא התפלל מנחה מתפלל ערבית שתים הראשונה ערבית והשניה לתשלומין.

108:1

ואם היפך לא יצא ידי תפלה שהיא תשלומין וצריך לחזור ולהתפלל אותה וכן הדין בכל מקום שצריך להתפלל תפלה לתשלומין

Atta chonantanu is meant to be said in the first shemoneh esrei, which is the maariv shemoneh esrei. When someone doesn't say atta chonantanu altogether, they would not need to repeat in order to say it. However, if one says atta chonantanu in the second shemoneh esrei, they are showing that their second shemoneh esrei was their maariv, in which case they davened their make-up mincha before the current maariv, and their mincha is invalid . Therefore, you should not say atta chonantanu in the second shemoneh esrei (O.C. 108:10 and M.B. 29).

S.A. 108:10

בדיל בראשונה ואינו מבדיל בשניה ואם לא הבדיל בראשונה והבדיל בשניה שניה עלתה לו ראשונה לא עלתה לו

[However, if you explicitly had in mind that the first was for Maariv and the second was the mincha make-up, and did not switch the order, you do not need to repeat shemoneh esrei and both count (M.B ibid).]