In the Padma Purana, Uttara Khanda, Chapter 236, Lord Shiva says to Parvati that He would incarnate as Adi Shankaracharya to teach the mayavadi philosophy:

mayavadam asac chastram pracchannam bauddham uchyate mayaiva kalpitam devi kalau brahmana rupina (Padma Purana 6.236.7)

Translation: "Mayavada or Advaita philosophy is an impious, wicked belief and against all the conclusions of the Vedas. It is only covered Buddhism. My dear Parvati, in Kali-Yoga I assume the form of a brahmana (Adi Shankara) and teach this imagined philosophy.

apartham sruti-vakyanam darsayan loka-garhitam sva-karma-rupam tyajya tvam atraiva pratipadyate sarva-karma paribhrastair vaidharma tvam tad ucyate paresa-jiva-paraikyam maya tu pratipadyate (Padma Purana 6.236.8-9)

Translation: "This mayavada advaita philosophy preached by me (in form of Adi Shankara) deprives the words of the holy texts of their acutal meaning and thus it is condemned in the world. It recommends the renunciation of one's own duties, since those who have fallen from their duties say that the giving up of duties is religiosity. In this way, I have also falsely propounded the identity of the Supreme Lord and the individual soul."

brahmanas caparam rupam nirgunam vaksyate maya sarva-svam jagato py asya mohanartham kalu yuge (Padma Purana 6.236.10)

Translation: "In order to bewilder the atheists, in Kali-yuga, I describe the Supreme Personality of Godhead Lord Krishna to be without any form and without qualities."

vedante tu maha-sastrera mayavadam avaidikam mayaiva vaksyate devi jagatam nasha-karanat (Padma Purana 6.236.11)

Translation: "Similarly, in explaining Vedanta scripture, I described the same non-scriptural and inauspicious mayavada philosophy in order to mislead the entire population toward atheism by denying the personal form of my beloved Lord."

Are there any similar verses in other scriptures saying that Lord Shiva would appear as a Brahmana to preach the mayavada philosophy?

In the Padma Purana, Uttara Khanda, Chapter 236, Lord Shiva says to Parvati that He would incarnate as Adi Shankaracharya to teach the mayavadi philosophy:

mayavadam asac chastram pracchannam bauddham uchyate mayaiva kalpitam devi kalau brahmana rupina (Padma Purana 6.236.7)

Translation: "Mayavada or Advaita philosophy is an impious, wicked belief and against all the conclusions of the Vedas. It is only covered Buddhism. My dear Parvati, in Kali-Yoga I assume the form of a brahmana (Adi Shankara) and teach this imagined philosophy.

apartham sruti-vakyanam darsayan loka-garhitam sva-karma-rupam tyajya tvam atraiva pratipadyate sarva-karma paribhrastair vaidharma tvam tad ucyate paresa-jiva-paraikyam maya tu pratipadyate (Padma Purana 6.236.8-9)

Translation: "This mayavada advaita philosophy preached by me (in form of Adi Shankara) deprives the words of the holy texts of their acutal meaning and thus it is condemned in the world. It recommends the renunciation of one's own duties, since those who have fallen from their duties say that the giving up of duties is religiosity. In this way, I have also falsely propounded the identity of the Supreme Lord and the individual soul."

brahmanas caparam rupam nirgunam vaksyate maya sarva-svam jagato py asya mohanartham kalu yuge (Padma Purana 6.236.10)

Translation: "In order to bewilder the atheists, in Kali-yuga, I describe the Supreme Personality of Godhead Lord Krishna to be without any form and without qualities."

vedante tu maha-sastrera mayavadam avaidikam mayaiva vaksyate devi jagatam nasha-karanat (Padma Purana 6.236.11)

Translation: "Similarly, in explaining Vedanta scripture, I described the same non-scriptural and inauspicious mayavada philosophy in order to mislead the entire population toward atheism by denying the personal form of my beloved Lord."

Are there any similar verses in other scriptures saying that Lord Shiva would appear as a Brahmana to preach the mayavada philosophy?