The Dove in Spiritual Form? P4 in Luke 3:22

The substitution of πνεύματι (πνι) for σωματικῷ in Luke 3:22 in P4 is interpreted by Bart Ehrman as a case of “orthodox corruption.” The text of P4 reads:

και καταβηναι το πνα το αγιον πνι ειδει ως περιστεραν επ αυτον

When “the Spirit is said to descend upon Jesus in ‘spiritual’ (πνεύματι εἴδει) rather than ‘bodily’ form,” Ehrman says, it “undercuts a potentially Gnostic construal of the text because there is now no ‘real’ or ‘bodily’ descent of a divine being upon Jesus” (Ehrman, The Orthodox Corruption of Scripture: The Effect of Early Christological Controversies on the Text of the New Testament (Oxford-New York: Oxford University Press, 1993), 143.

However, shouldn't we rather expect the adjective πνευματικῷ (“spiritual”), as more natural here being the opposite of σωματικῷ (“bodily”), rather than the noun πνεύματι (πνι).

In 1 Cor 15:46-47 various forms of πνευματικός are written with nomina sacra (πνκος/ πνκον) in P46 (curiously not in 1 Cor 15:44). Similarly, the adjective is written with nomina sacra in 1 Pet 2:5 (πνατικος/ πνατικας) in P72.

Is there any other way of translating the passage in P4?

The first editor of the complete text, Jean Merrell, suggested πνι was a dittography (πνα πνι). That explanation is difficult because of the intervening το αγιον and the two distinct forms πνα πνι.

On the other hand, this scribe created at least one nonsense dittography elsewhere, in Luke 3:27 the scribe substituted τοῦ οὐ Ῥησαῦ for τοῦ Ῥησά.

What do you think about this passage?