Did Francisco de Peñalosa compose the Credo of the mass Rex virginum?

One of the two composite masses Rex virginum of Iberian origin features a Gloria and a Credo traditionally attributed to the composer Francisco de Peñalosa (d. 1528) – the other movements being credited to Pedro de Escobar (Kyrie), Pedro Fernández de Castilleja or Pedro Hernández de Tordesillas (Sanctus), and Alonso Pérez de Alba (Agnus). All the movements that comprise the 91 mass are unica, and appear copied in the manuscript E-TZ 2/3 (fols. 200v-209r) under the name ‘Misa de Nuestra Señora’. The composers’ names are written both in the Table of Contents (only Escobar and Peñalosa) and in the body of the manuscript, at beginning of the each movement.
A closer look to the inscription at the Credo (fol. 204v) reveals that the name ‘P.losa’ has been scratched out, a detail that has gone unnoticed up to now. This correction (within a manuscript that is generally considered reliable despite a few conflicting attributions and corrections) raises the question of the Credo’s ascription. Furthermore, the style of the movement is unlike Peñalosa’s standard compositional practice (as previously stated by scholars, the dissimilarity between the Gloria and the Credo is immediately noticeable). This paper will examine the Credo of the mass Rex virginum in order to shed light on the piece’s authorship so testing the hypothesis that the scribe could have been right in discarding the attribution to Peñalosa.