[Advaita-l] Confusion regarding Shvetashvtara upanishad bhasya

[Bhaskar YR]

Traditionally this Upanishad Bhashya is not considered an authentic work of Shankaracharya.  Hence, it is not a part of the study of the Prasthana Traya Bhashya.

praNAms
Hare Krishna

Any specific reason / justification for this from traditional scholars??  Anywhere it is discussed why it is not from the pen of prasthAna traya bhAshyakAra??  

Hari Hari Hari Bol!!!
bhaskar