assalam alikum is some one a kafir if they don't believe in seeing allah face in Jannah because the mutazalites don't belive nor the shia so are the shia disbilivers since they don't believe in seeing allahs face

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

Undoubtedly, denying that we will see Allah in Jannah is a religious innovation; many texts in the Quran and the Sunnah confirm this fact. However, simply denying it, does not make one a disbeliever; rather he is an innovator and must repent to Allah and go back to the belief of the people of the truth (Ahlus-Sunnah wal-Jamaa’ah).

Some scholars stated that it is disbelief to deny seeing Allah in Jannah. This means that since saying that Allah cannot be seen in Jannah is a statement that contradicts many religious texts which confirm seeing Him, then it is disbelief. However, the individual who says this is not a disbeliever. Shaykh ‘Abd Ar-Razzaaq Al-Badr said: “Ahmad ibn Hanbal said: ‘Whoever says that Allah cannot be seen in the Hereafter is a disbeliever.’ This is the ruling of the statement itself, because it is denying something which many (religious) texts confirm to be true and the scholars of the Muslim nation have collectively confirmed it to be true. However, the individual who denies seeing Allah is not ruled to be a disbeliever immediately until the matter is clarified to him. This is because innovators have caused misperception to people and authored books that include many confusing issues.” [End of quote]

Allah knows best.