Does saying "Allahumma salli" with the added 'ya' (اللهم صلي) corrupt the meaning because it is for the feminine, and what is the validity of the prayer of one who says it in the second Tashahhud?

The established and common practice for "Allahumma salli" (O Allah, send prayers) is to omit the 'ya' (ي) because it is a command verb built upon the omission of the weak letter, as in Allah's (the Most High) saying: (And pray for them). As for affirming the 'ya' as "salli" (صلي), it has a basis in the Arabic language, as some Arabs permit treating a weak verb as if it were sound. It has also been recited this way in some readings, such as Ibn Kathir's recitation of "yasbiri" (يصبرِ) with a 'ya'. Furthermore, the 'ya' can be affirmed for the purpose of extending the kasra (short 'i' vowel) of the 'lam' in "salli." This does not invalidate the prayer or the supplication because it does not change the meaning.